Astrophotography workflow in Affinity Photo with James Ritson

[Music] [Music] [Music] [Music] [Music] you [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] you [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] you [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] hello all thank you for joining this livestream thank you so much for attending my name is James and I'm the product expert for affinity photo that basically means I look after the app in terms of learning materials demo training and much more I'm also an avid photographer and recently if I just scrolled down earlier this year I started to get into Astro photography now previously I had kind of dabbled a little bit in terms of Polaris star tracking that type of thing and that was fairly rudimentary but at the start of this year I got a an equatorial mount and a star tracker and I started to experiment with stacking long exposures of deep sky objects and that's what we're going to do today we're going to look at a workflow that I've developed in affinity photo to process images from in this case deep sky stacker if you're an astro photographer yourself you'll probably be aware there's various software to actually stack your raw images and apply your calibration frames I'm using deep sky stacker as I find it fairly intuitive and what this is is the Orion Nebula and the running man above it although you can't actually see the running man yet will tease the detail out as part the editing process and I've saved it as a 32-bit rational TIFF file now 32-bit is important because it gives us extra precision which is really really really necessary when we're tone stretching very sort of underexposed astrophotography images it helps avoid banding and other artifacting and that type of unpleasantness that we see in our images so what I've done here then is you can see an affinity photo we're working in the 32-bit at the moment this is quite important because essentially apart from one single step we're going to be working in 32-bit for our entire workflow and if you've used other software to edit your astrophotography images you'll know that's quite unique so let's start then first of all I'm going to add a simple curves adjustment to push the overall exposure up or the overall gamma up and I'm going to use my shortcut for that so your command M okay and on my curves dialog here I'm just going to add a node roundabout here push those tones up and you'll find this on lots of deep sky objects actually the Orion Nebula has the Orion core which is very easy to blow out or overexpose so what I want to do here is just add another node and kind of tail off that curve there so that we don't end up you can see what's happening here so we don't end up clipping those tones too early on in our tone stretching process so I'm going to move them down here like so okay and then I'm going to add essentially my process it's a little it's a little rough around the edges but it essentially involves stacking lots of curves adjustments together for the initial tone stretching process so another curves adjustment and this is another technique that I've recently started using and I must admit for all of our Jean Rizzo photography I've never ever used the picker on the curves dialog but it's incredibly useful for this type of imagery so I'm going to enable the picker here and I'm going to sample from the background you can see I've just clicked there and then I'm also going to sample from the very faint Nebula detail here okay that's going to let me push these tones up gradually but of course for each curves adjustment I do want to kind of add another node and make sure again that we're not blowing out that core detail too early on in the process okay so the other issue that we're going to have and moving forward with this image is it's incredibly red and the reason for that is that I shot with a full spectrum camera I had an ultraviolet and infrared cut filter on but in deep sky soccer when you shoot with a modded or a full spectrum camera it recommends not to use the cameras why pants information in the exif data and so what we end up with is a very red image luckily that's really easy to correct we want to put a white balance adjustment above the initial pixel layer that we're working on so layer new adjustment layer white balance and you'll see I've actually set up a shortcut for that because I use it so frequently on Mac I'm using option W so let's add our white balance adjustment and I'm gonna just slide both the white balance and tint down until we neutralize the the background and it's very possible that I will need to come back and revisit the white balance once I do some more tone stretching because as we start to stretch the tones even further we'll bring out more of the reddish nough switch we don't want so another curves adjustment I'm going to use the picker again and this time I'm gonna just drag and sample here now you don't always have to do code like a dramatic tone or adjustment I tend to kind of add this as an anchor point so it doesn't even have to move from the diagonal line going through the curves graph here what's more important is that I anchor that tonal point and then that gives me more free rein to push the faint nebula tones away from that background detail and again I'm just going to use another note here to tail off the highlights that we're pushing up okay I'm thinking at this point then I might add one more curves adjustment I reckon because right down here I don't know if you can see this on the live stream it's very faint there's some really faint red nebula detail so we're going to try and bring that out once again I'll use my picker pick off the background there just anchor that and then go right into this very faint detail look at that that's very dramatic yeah like I say quite dramatic the the thing we have to be careful of is it's very tempting to push are stacked astrophotography images too far and then we end up with kind of meaningless noise in the background and it might look ok at the moment but that will come back to bite us later once we do more processing one of the things I'm going to do I'm going to show you is how to remove the gradient going across the length of the image so although instinctively I probably could take the tones maybe a little bit further I'm actually probably going to leave it there because you know surely through purely through trial and error yeah I just don't want to end up with too much fuzziness or noise in the background detail so I'm gonna go back to my white balance adjustment down here and I'm just going to neutralize that a little bit more like so I'm gonna leave a tiny bit of red in there that I'm not gonna neutralize it entirely and because it brings out some kind of like some nice reddish hue in the the nebula detail here and we don't actually have to worry too much about the balance of the sky detail because we're going to remove that anyway okay now before we go on to the really exciting part which is the the synthetic flap frame subtraction we're going to probably do a little bit of denoising I reckon the year in fact before we do that I lied I'm actually going to add one more curves adjustment and I'm just gonna push this a little bit further just a tiny bit like so I'm not just gonna do it manually in by hand this time yeah okay that works that works for me so I'm going to do some denoising now some luminance and some color denoising and for that I'm going to duplicate the background pixel layer command J I'm just going to rename this layer let's stay organized here and the reason I'm actually doing this destructively rather than adding it as a live filter layer because we could add it as a live layer and that would be non-destructive the reason I'm doing it destructive is because we can be more aggressive more effective with on noise reduction and you'll see that I add a clarity filter later as well I'll get into that again so let's go to D noise move the sliders back let's zoom into a particularly noisy patch yeah we can see that okay so I'm going to drag the color slider up until that : oiz disappears you can see there's the color noise in the background detail and I can just remove that quite easily like so I'm just going to answer a question from the chat actually while I'm here what lens or telescope did you use didn't use a telescope I used a Canon 400 mil F 5.6 lens wanted to get really detailed with a sigma MC 11 adapter so that I could put it on my sony a6000 the sony a6000 is the modded or the full spectrum camera basically and because of the crop factor of the aps sensor it becomes I think equivalent six hundred mil so it was quite a reasonably tight focal length for the Orion Nebula and to be honest it's about as far as I can go with the the star tracker in the equatorial mount I've got I think these exposures were 25 seconds long you can get away with that because the Orion Nebula is such a bright object anyway but at that focal length I was I was struggling really the only reason I actually managed to get 25 seconds was because I shot this in my back garden and it's nice and protected from the wind as well I sort of wedged my set up between the shed and defense and it would just get it just kind of took the edge off the the wind during the winter period so anyway where were we yeah luminance noise let's tackle that as well so okay I'm just gonna you got to be careful with this it's tempting at this point to go oh yeah let's just wipe out all of the noise like so but the problem is once you you do you're flat frame subtraction nor you your synthetic flat frame subtraction and then you add a clarity you add sharpening and so on if your image doesn't have any kind of natural texture to it it really becomes quite obvious and it just it just doesn't have the same appeal or the same clarity to it so I tend to keep luminance noise reduction at around maybe 15% give or take so it's just kind of taking the edge off the noise but not excuse me eliminating it entirely okay I'll click apply and now I think it's time for yeah I think it's time to create that synthetic flat frame so what we're going to do is merge all of our changes so far by going to layer and merge visible okay I'm what should I call this let's just call this merged I'm gonna copy this layer so on Mac that's command C and I'm gonna go to filters and new from clipboard okay now I'm gonna explain my reasoning behind this okay so I mentioned that we're working in 32-bit and we're pretty much going to work 32-bit from start to finish but there is one filter that we cannot use in 32-bit that we need for this and that's the median filter so median operators are incredibly expensive or very performance degrading to implement especially in 32-bit precision so we can't use it but what we can do is create a copy of our changes so far remove the deep sky objects from it and then run the median filter on a 16-bit version convert it back to 32-bit and paste it back in to use it so I'm going to get the selection brush tool here and I'm just going to make a selection of my deep sky objects so that's the Orion Nebula the running man and I've got a bit of a dust spot up here I'll tell you a funny story about that in a minute and once I've got my selection I can just go to edit and in paint it's going to take a a few seconds so I'm just going to look at the chart see if there's anything I can address no okay I will actually just explain that the reason I haven't used the inpainting brush tool if anyone's experimented with affinity photo or you use it already you probably go straight for the in painting brush tool which allows you to paint over areas and remove them I tend to do a selection instead because you might have multiple crucial sort of deep sky objects in your image they might be sort of dotted around and it's just kind of more economical really to select them all at once even if they're a part in the image and then in pain them altogether it also means that you don't end up accidentally use sampling one deep sky object when you replace another huh can sometimes happen okay so let's deselect using command D and now true to my word if we try and apply median blur filter we can't do it is grayed out because we're in 32-bit so we can go to document and convert the bit depth using convert format to RGB 16 okay let's click convert and now what this allows us to do is use median by the way an alternative technique or you might have read about is dust and scratches essentially they're the same thing it's basically a median operator it's just of dust and scratches has a couple of additional options which we're not actually going to use here at all so we may as well just stick with median blur okay it's already actually the slide is already set from when I practice this earlier can you tell so what we do with median blur is we drag the radius up until we eliminate all of the stars and then we click apply and also I've not experimented with other astrophotography stacking software so I don't know if it's a common theme but as part of the stacking process and during the alignment deep-sky stacker the final images have some kind of meaningless information on the very borders of the image and that's kind of shown through because we're applying a blur not to worry all this means is we basically just have to crop into our final image slightly so the other thing we might notice is again I'm not entirely sure if this will come through on the live stream but there is some banding present having just run the the median blur and this actually clears up very nicely if we just convert this document back to 32-bit click convert ok and now I'm going to use command C to copy my new layer here I'm going to close this document down and paste it into my main document ok as you can see we've got those four corners that we need to get rid of so see for the crop tool and I'm just going to drag in from the bottom corners like so then hit return to commit the crop ok let's call this flat this layer ok and now we just need to move it underneath the merged pixel there because what we're going to do is use a filter called apply image so one way is to just drag on the layers panel keep your cursor to the left and you can drag it underneath like so I prefer to use keyboard shortcuts to speed up my workflow so on Mac that's command + left square bracket then I'm going to select the merged pixel layer go to filters and apply image ok what we can do on this dialog is drag the flat layer onto the dialogue to use it and then we want to set our blend mode to subtract ok for her so a couple of things to know here one is that this does effectively remove our gradient because what we did was create like a synthetic flat which had the gradient profile and if we subtract it from the main image we of course subtract the gradient fine the issue is it subtracts to pretty much pure black and this does not look very good at all now if you follow tutorials from a certain other piece of image editing software you might be aware that the solution to this is to use an offset slider we can you know don't panic we can achieve that in affinity photos apply image dialog by checking the channel equations and what we can do is add an offset to each channel individually so for example I might add an offset of naught point one we use values between naught and 1 and we can use decimal values or floating point values as their call okay so that will offset the subtraction and it probably looks a bit too bright so depending on your own imagery you might have to experiment with this I've found for this image a value of maybe naught point naught 3 tends to work quite well yeah I mean we could probably we could probably try slightly higher but I might just go with this value the great thing however about using channel equations is let's say you were working with an image and you've got quite a lot of you photographed something that has a lot of hydrogen alpha emission and you want to retain as much of that red channel information as possible you can actually add an offset or a bias to one of the color channels so for example if I was on the red channel here I could add not point not 4 instead of point not 3 and that would just give my whole image a slight red tint which is useful if you want to kind of tease out that very faint red detail we don't really need to do that for the Orion Nebula though so I'm just I'm just trying to evaluate this so just zoom out is so a good little technique actually I was going to explore this at the end it's quite applicable here as well sometimes to get a better perspective I find it helps to just zoom your image out and look at it in very a very small rendition and that might just kind of help you for example here if I try a slightly higher value yeah I actually know ya know I might yeah so that's helped me decide that that would be too bright so I'm gonna stick with point zero three and click apply okay the next step we're going to do is add some clarity or structure enhancement and like I did with D noise I'm actually going to duplicate that merged pixel layer and call it clarity so again if I wanted to work totally non destructively I could add a live filter layer a live clarity filter okay but the problem is there has to be a concession because it effectively has to render in real time in the document stack the layer stack and so you can't be as aggressive with it so what I prefer to do instead is actually duplicate and run the destructive clarity filter okay and it will already be set to a hundred percent there we go so as I drag up watch what happens to the texture under structure of the image we really start to bring out that very faint nebular detail especially around there I mean that looks really dramatic now of course we don't want it to affect the rest of the image because we're bringing up quite a few dust spots here and also these stars are perhaps some they're fighting too much for our attention so I'm going to click apply and then what I will do is hold alt or option while I add a mask layer down here and that adds an empty mask that then leaves us free to use the paintbrush tool over here just increase my brush width and I just need to make sure I'm painting with white so on the color panel you can toggle between these two colors very quickly or I prefer to use X on the keyboard to toggle and then I can paint in over the areas I'll just zoom in so you can see that over the areas I want to affect of course we have a problem it's that dreaded Orion core again that's getting overexposed so not a problem we can just use X to flick back to black on the color panel didn't mean to name check and album there and then we just paint out from the Orion core like so okay now the other issue that I'm going to tackle now is I'm going to do some in painting or dust spot removal so I'll just see if there's anything I can address in the chat now okay so basically when I actually shot this it was a kind of like a la spur-of-the-moment decision I originally was going to do a much wider view of the Andromeda galaxy and then I decided last minute as you do no actually I haven't got anything with my modded camera of the Orion Nebula and I want to see if a modded camera can bring out any more nebula detail so I basically changed lenses on the fly set my tracker up again very quickly polar aligned all of that but of course I didn't use a rocket blower and that there were so many dust spots on the sensor honestly if you see one of the light frames there's just dust spots everywhere now our shot calibration frames are shot darks are shot flats are shot bias our shot dark flats and on the flats you can see all the dust spots very clearly but in a way it's almost the fluff frame calibration the division I think or subtraction it's actually kind of inverted the dust spots so now they appear is like these these blobs so this is just one example of what can go wrong when you do this kind of Astro photography so I'm going to in paint non-destructively and for that I'm going to create a pixel layer down here and then with my in painting brush tool why can do is on the context toolbar up here I can change this option to current layer and below and you can do this for all the retouching tools in affinity photo so now I've got my blank pixel layer but if I use my in painting brush in fact although this is nice I'm going to get rid of it anyway because I don't want too much kind of fighting for attention I've got a kind of like a red smear up here that I'm going to also get rid of and I'm just going to sort of browse through the image yep I've got a very faint the spot there and you can kind of see them here they're the kind of disturb the noise profile in the image these are really bad look at these okay so we're just going to in paint these out so anyway back to my point about non-destructive in painting essentially what we can do is in paint and sample from the layers beneath the layer within painting onto so as I am in painting like so just see if there are any more as a couple down here although I'm probably being a little bit picky now yeah okay so basically we've got this pixel layer let's rename it again to stay organized for this session if I select that layer by holding option and clicking on it you can see all of the in painting work that I've done but it's on a separate pixel layer so we haven't had to merge our changes once again and then do some more in painting on it destructively that type of thing and it means that excuse me if we if we ever had a scenario where we needed to go in and erase some of that in painting we could do that very easily I've just spotted another spot up here I'm trying not to be too perfectionist about this at the moment okay now the next thing I'm going to do is use channels and for this I'm actually going to merge our changes again okay this layer I'm just going to call temp for temporary we won't end up using it for anything else really and I've got my channels panel open down here and what I can do is extract one of my color channels as a grayscale layer so what I will do is right click red and create a grayscale layer from it okay let's just call this red and then I can set the blend mode to luminosity and it will blend through the luminosity of that red channel information from its grayscale form so what this does if I just zoom in is it's it's very subtle but it just kind of again it's all these little things that you kind of build up to produce the final image so if I turn it on you can just see some of that very faint nebula detail becomes ever so slightly more visible now the problem is because we've added luminosity we've also D saturated so we need to take care of that don't worry we'll get around to that the other issue going back to the Orion core again is that we're now clipping the Orion core if you can see right in there it looks a bit ugly it just clips to kind of flat white so to counteract this I will add a mask layer get my paint brush tool and I'm already set to black that's good I can just subtract away from the mask and get my nice punchy white Orion core back okay so I mentioned tackling the saturation and that is exactly what we will do I'll add a nature cell adjustment now you can do this from the layer new adjustment layer menu or you can use the shortcut so I'm going to use command u on Mac or control U on Windows and I don't have any specific color regions I want to avoid so actually I'm gonna stick with my master option here and just bring the saturation up like so until we just add back in that nice richness of color that we lost by doing the luminosity blend mode on that grayscale layer we've got some blue hiding in here as well so the next step is astrophotography purists will probably start yelling at their screen in a moment I do this with all my kind of all my John Resort photography I like to enhance regions or tones using brushwork and astrophotography is no exception so I'm going to add a blank pixel layer let's call this painting get the paintbrush tool just increase my brush width and I'm going to hold alt or option + click drag to bring up my color picker I'm going to sample from a nice sort of rich purplish color a purpley red color on the Orion Nebula here then release the mouse button and that becomes my active color on the color panel as you can see up here I'm going to tweak this slightly to make it a little bit deeper then on my pixel layer I'm gonna set the blend mode to overlay okay now if I brush over at the moment you can see that effect is gonna be way too strong it's going to take our nice astrophotography image from looking quite nice and pleasing - just looking completely comical which of course we want to avoid so we can take the opacity down maybe to about let's try 50% I mean this is a great thing about working with layers is that if the effect is too strong or if it's too weak it's not a problem we can just go back in and adjust to the effect I'm already thinking this is too strong but we will persevere for now we've got some very subtle shades of blue and light purple up here let's see if we can't enhance those so on my color panel here I've got the HSL wheel I'm just going to see if I can add a little bit more color to these areas again this is so subtle so so subtle let's zoom out and get some perspective okay yeah so straight away this looks far too strong not a problem let's just take the path he down and we can scrub the apostille Eider so we get a real-time preview of the result that we might want to end up with I'm thinking maybe just shy of 25% something like that that might look quite nice yeah okay also just up here just switch back to my brush tool let's pick a nice deep blue and see if we can't just enhance the blue up here as well again I mean which is talking very faint differences here is before and the after okay looking good so far we're pretty much coming to a close for the edits that I wanted to make on this image one thing you can do rather than constantly use curves adjustments is sometimes a simple brightness and contrast adjustment will suffice we'll try that here so let's add a brightness and contrast adjustment and I'll just increase the brightness and the contrast like so and again if I just show the before and the after he just adds a nice little bit of glow a little bit of punch to the nebula detail here in fact why don't we take this a little bit further like so okay now if this wasn't nerdy enough already we're about to go into super nerd territory are you ready for this okay so I'm going to add a non-destructive unsharp mask filter this is for our final output sharpening but watch what happens if I have a radius of 2 pixels and a factor of 2 we get these horrible black halos around all of our star detail now granted is probably less noticeable at 100% zoom I am exaggerating this because I'm near 600 percent zoom but this is because we are compositing in linear space so as opposed to working in 8-bit or 16-bit when we work in 32 bits unbounded floating-point precision we composite in linear gamma okay whereas 1r in 8 and 16-bit all the compositing is done in gamma corrected nonlinear space and I don't know if you've ever tried to HDR merge your images then try and add some sharpening afterwards but you may have seen this even in kind of like landscape photographs that type of thing with affinity photo and it's because we're in a linear compositing at the moment now previously what I was doing was I at this point I would flatten my document down and I would save a copy of it and convert it to 16-bit just so I can add my final sharpening and that type of thing and maybe do some cropping and of course that's not great for a none destructive workflow because you know you're making another copy of your document that's an implication for file size storage that type of thing and then I found this just sort of worked out this really cool work around using the procedural texture filter so in affinity photo we have a procedural texture filter where you can essentially write functions and equations yeah you can you can go quite far down the rabbit hole of this but essentially what I'm going to do is add a live procedural texture and I want to make sure it's underneath my unsharp mask I'm just going to turn the unsharp mask off for now okay and take a sip of water so on the procedural texture dialog I want to click this plus icon three times my image goes black that's fine this is for red green and blue and what I want to do is this harks back to secondary school mathematics I'm going to raise each color channel so R to the power of 0.45 recurring we won't bother with the recurring we'll just repeat the the two digits twice do the same for green and the same for blue now if anyone has studied linear versus nonlinear gamma transforms that type of thing and compositing you're probably screaming at the screen right now saying that's not technically accurate and you can't just apply one you know that the power transform is kind of like a median value it's not absolute across the entire tonal range etc but this is close enough and what we're doing here is you'll notice our entire image has become much brighter and washed down and what we're doing is we can now composite the unsharp mask in nonlinear gamma corrected space or a rough approximation of that so if we have a look at our stars around here notice that the if I turn on shot mask on there's some slight kind of black edge to the the detail here but it's nowhere near as pronounced as it was previously and we just turned procedural texture off so you can see that before and the after look at that and in fact even gives our stars a bit more of a punch and glow which is kind of an unintended unintended side effect really so now all we need to do is get back to our original linear space and for that we're going to add another procedural texture filter on top of the unsharp mask and then add our three equation channels again and this time we're going to raise each channel to the power of two point two okay why two point two because two point two is the reciprocal value of not 0.45 recurring to calculate this we can just do one over not 0.45 and there we go we get 2.2 recurring and that's how you work out reciprocal power values if you wanted to try this yourself okay so we can close that down now and I'm just going to command select to choose both of these procedural texture layers and I'm going to turn them off and you're going to see that before look at that with those black halos and the after so we've pretty much gotten rid of those nasty distracting black halos around our star detail so that's a great little tip because it now means that you can do your entire image start to finish in 32-bit and that's really useful and I appreciate that's you know quite time consuming and perhaps a little bit daunting if you haven't done that type of thing before so I'm going to go ahead and delete all them and if you follow the link in the description of this video you will find the free astrophotography macro pack that i've provided so if you import that into your macros library you've got all kinds of options here you've got star motion deconvolution that's really useful for images where run your exposure time was maybe slightly over what it should have been and you've got slight star trails and but also you've got nonlinear unsharp mask and if I add that that basically does the entire procedure that I just showed you within a macro you can see I've got my sharpening back here so you don't have to worry about getting the values right getting the equations right over the rest of it you can just download these macros and run the nonlinear unsharp mask what you can also do is if I just go beneath here I've got a nonlinear compositing macro and that sets it up so that all you need to do is put whatever adjustment layer or pixel layer in between these two layers and that will be composited in gamma corrected non linear space the reason you might want to do this is I tell you if you've ever tried to use curves in 32-bit you might have done if you've merged any bracketed exposures together for HDR but curves seems incredibly sensitive and that's because a lot of the the curves detail is going to be in the first half of your histogram here well if you're in nonlinear space you should find that it's far less sensitive and it's perhaps a little bit easier to push the tones around and manipulate them okay I'm gonna hide my library panel now that's my main image finished I've actually decided I don't like that curves adjustment so I'm going to delete that get back to my original a tonal look now the final thing I want to do is rotate this image so I'm just going to give you a bit more of a boring backstory if I had followed the right ascension and the declination of my star tracker at the time I would have ended up with the more typical composition you have for the Orion Nebula and the running man which is there side by side on the left and right but I was a little bit cheeky and I rotated my camera and lens within the tripod collar so that I was shooting purely horizontal landscape and it's ended up with the running man on top here and to be honest I don't really like that composition I prefer the side-by-side so all I do is go to document rotate anti-clockwise get my crop tool and just crop in like so and there is my finished astrophotography image but of course regardless of what genre of photography you're editing or whether you're compositing I would always recommend zooming out you know coming back going to make a cup of tea or whatever your preferred beverages coming back with a fresh set of eyes and new perspective on it export your images to your phones your tablet's any other kind of medium perhaps a TV will cut it on there because you'll get a different perspective and it will help you gauge whether you want to come back and change anything at a later date I might look at this later and go what was I thinking you know it's um maybe the background is too bright or maybe it's too dark you know so I would always recommend to try and gain yourself a fresh perspective rather than just exporting here and now and saying it's done okay thank you very much for watching the session but I'm just going to show you a little bit of a bonus if you're prepared to stick with me so at the very beginning of this I mentioned I previously did some Polaris star trails that was about two and a half years ago and of course with the lockdown in the UK at least we've kind of been stuck and I haven't been able to go out during the night and shoot my Astro photography that I want to so I thought well you know I'll just make do with what I've got and I set up everything in my garden and got some flowery star trails about last week so for doing that type of photography you can also use a finiti photo to very quickly get your stack into a document you go to file a new stack you add your images in here you don't need to align them because you will shot them on a tripod for long exposure you uncheck that and then you click OK and what it does is it gives you a document with a live stack group and all you do is you click here and you change the operator to maximum okay and that blends through all of the brightest pixel layers which of course will be the star trails in our imagery here but you know I'm not going to stop there because why would I let's take this a little bit further okay so again astrophotography purists are probably going to get very upset with me as you may or may not you may or may not know but the actual polaris star is not actually on the the axis of the Earth's rotation is ever so slightly offset and of course that means that it does move very slightly so when you stack together exposures over say an hour or two hours you've also got the polaris star that moves as well and I don't like that compositionally I want a nice sharp star bang in the middle of all my spiraling stars here so I'm going to go to the very first exposure in my stack duplicate it and I'm going to bring it out on top like so there's my nice Polaris star that's very sharp get the elliptical marquee tool and I'm going to hold shift while I make a selection I can move it around after the fact as well if I haven't quite got the selection dead-on okay and then I'm going to invert the pixel selection I'm not going to bother being non-destructive here to be honest and masking it because we only really need the star from this layer we don't need the rest of the layer contents so delete okay command D to deselect then V to get the move tool and I'm just going to move this into the center roughly here okay and then we need to get rid of the trailing Polaris star here so I'm going to use that same in painting technique I showed you earlier new pixel there the in painting brush tool and set to current layer and below make my brush smaller and I'm just going to in paint over the Polaris trail sometimes this happens it samples from an adjacent area and you get this just go over again if it does if it absolutely refuses to sample from a blank area of the sky you can use the clone brush tool located here and you can do exactly the same procedure so set it to current layer and below okay so next this is this is one of the very unique things about affinity photo that I really do love I want to add some radial blur to these star trails because if we zoom in we'll see they're quite jagged and I want more of a kind of a smoother appearance so I'm going to add excuse me a live radial blur okay that's nothing new you've seen the live filter layers before and I'm going to check preserve alpha but the great thing about the radial blur filter and all of the filters in photo is that essentially you get feedback on your full resolution document on your screen so there are no kind of like mini thumbnail previews or like abstract representations of your image you see the effects happening on the image so if I drag angle up instantly I can get feedback on how far I want to go with my radius angle I can drag around on the canvas as well to move the origin point of my radial blur I've got a bit of a job actually finding Polaris like this so I'm gonna take the angle down there we go zoom in and just drag it over Polaris like so I think I actually just missed that there we go and now I can drag my angle up to get my preferred degree of radial blur okay that looks really nice and slick but of course because it's a live filter there I can go in double click it and change it later if I want to okay what should I do additionally I think I might add a curves adjustment so again I'll use my shortcut for that command M let's just bring these tones down and then up like so I might add a live clarity so layer new life filter layer sharpen and clarity and this will just help bring out some of those fainter star trails I don't know if you can see that but I'll just zoom in so let me show you the before here and the after so it just helps kind of thicken up the composition a little bit by revealing some more of that fainter star detail okay you know what finally let's add a brightness and contrast adjustment I'm going to use my shortcut for this so option B just to add a little bit more punch to this image and finally it's probably too strong in the color for my tastes so command you for an HSL justement drop the saturation down slightly like so okay and now is my finished polaris star trail composition actually not quite finished I think perhaps it's a little bit too bright so let me just go in add a bit more contrast less brightness there we go okay finished hands off I'm happy with that by the way I will just mention because I have been using them throughout if you go to preferences you can on this dialogue setup your own keyboard shortcuts so I do this all the time especially for I do a lot of compositing and that type of thing so for example on the layer over here I will shortcut some additional adjustment layers as well and also this is really useful if you if you like to clip layers inside other layers so if you do a lot of compositing work you want to put adjustment layers inside your composite pixels that type of thing your cutouts check out the arrange dialogue and insertion inside that one there because essentially what that does is it allows you to use your shortcuts so shift I and then when you add your next layer like a curves it gets added as you can see here into the layer that you just had selected so that's a really quick way of quickly clipping layers inside other layers just wanted to share that technique with you because I use it all the time for not just compositing but are all kinds of workflows basically okay and I really will bring it to a close now so thank you so much I appreciate you all coming and watching this live stream I hope you're all ok and safe during this ridiculous time crazy time thank you so much for watching and take care all of you stay safe thank you [Music] you

Channel: Affinity

Views: 33,004

Keywords: Astrophotography, stacked astrophotography imagery, astrophotography tips, astrophotography workflow, photo editing, photo editing tips, astrophotographer tips, Affinity Photo, using Affinity Photo, astrophotography techniques, tone stretching, synthetic flat frames, structure enhancement, masking

Id: kBV6p5T_Xkk

Length: 80min 47sec (4847 seconds)

Published: Mon May 04 2020