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ch22

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  1. Additionally, switching to English in Preferences dialog makes the Overlay item reappear in the drop-down list with seemingly the expected behavior.
  2. I confirm. The second occurrence of the "Superposition" (Screen) mode is not a mere mistake in the drop-down list names, it really calls for the Screen mode.
  3. In my opinion, the new filter is much less satisfactory than the previous version. The only progress I agree is that the halos along the discontinuity lines have apparently vanished. In this message, I report a behavior that seems to me anomalous. When I apply the Shadows & Highlights live filter to a homogeneous patch R = G = B = 5 with a 100% strength , the luminosity does not stabilize at all when the range goes from 0 to 100%, contrary to what happened with version 1.6. The figure below summarizes what happens. Incidentally, the figure also shows that the 100% range is limited to the medium gray, i.e. lighter tones are not affected. Why not to allow the filter effect to cover the whole range from black to white?
  4. I confirm we are speaking of the new S&H filter. Below is a picture showing the effect on a gray chart, with the original and the modified chart together with the histogram of the modified chart (this histogram comes from Photoshop). The ray widening is characteristic of the action of S&H filters.
  5. ch22

    Raw Photo is very dark

    Actually, since a RAW file does not contain any ICC profile, the luminosity and the colors of a RAW file just opened does not matter very much. It's only at the output of the raw software that a ICC profile is added to the file and that RVB components are given a true color meaning. However, the camera JPEG file or the display by the system commodities or Adobe software (and many others, of course) are in reasonable agreement and thus offer a convenient reference with which Affinity Photo should comply — and unfortunately it does not always. Under MacOS and with Serif RAW engine, I observed nothing special with NEF, CR2 or ORF files, but I actually got this odd darkening with RAF files. However, it disappeared when I switched to the Apple RAW engine. Below are compared screen copies for RAF and CR2 between AP 1.6, AP 1.7 and Photoshop (in this case, with no correction) and a screen copy with the Apple RAW engine :
  6. The Shadows/Highlights Filter has been rewritten and I find its new version far less satisfactory than the previous version (incidentally, I hardly understand how such a filter may run without the Radius glider) I enclose below an example of comparison. Increasing the correction intensity in 1.7 would lead to a picture even more grayish
  7. I'm just one year late, roughly, but I discovered this discussion only recently by chance and I'm grateful for the appreciation. Actually, I wrote these tutorials with true beginners in mind and I tried not to lose them when advancing in the intricacies of AP. Now, by the beginning of 2019, many of the tutorials which were missing by the time of the jmmermet post are now in line. Only for french speaking people, I'm sorry, nobody is perfect ! Let me repeat the adress http://www.oitregor.com/numeric/affinity_photo/contenu.html
  8. Under MacOS, I compared various prints of a gray chart on a matte paper, on the one hand from Photoshop with perceptual intent (without black point compensation), and on the other hand from AP, either perceptual or relative, with or without black point compensation. All of them are practically identical.
  9. Sorry, my reference to the Photoshop model was somewhat irrelevant... and it does not matter. The key point is, whatever the actual model used in the AP colorimetric model, that putting saturation to 0 in the HSL adjustment makes the (Max, Mid, Min) trio replaced with (Max, Max, Max). This can be checked in a practical way by monitoring what happens to RGB components of a color sample in the Infos panel. Then, switching to the difference blending mode makes the original trio replaced with (0, Max-Min, Max-Mid). Since the largest component is now Max-Min, the second HSL adjustment puts the three components to Max-Min.
  10. Alfred : thanks dmstraker : finally the sorcery can be easily explained, provided that HSV model is really the cylindrical HSL model used in Photoshop Adobe color requester. In this model, if the RGB components are sorted in decreasing order as (Max, Mid, Min) — think of these components as reduced quantities varying from 0 to 1— the HSL components can be then written as H =(Max-Mid)/(Max-Min) ; S = Max -Min ; L = Max where H actually is the decimal part of a reduced hue varying from 0 to 6, with an integer part depending on which colors correspond to Max and Min components. This formulas can be inverted as Max = L ; Min = L-S ; Mid = L-TS Now, following the dmstracker process : (i) putting S to 0 in the first HSL adjustment makes the three components replaced by L (the largest component) (ii) switching to the Difference blending mode replaces the (Max,Mid,Min) trio with (0,S,TS). Since T<1, the largest component is now S (there is also a hue jump but it does not matter) (iii) opening the 2nd HSL adjustment and putting the Saturation slider to 0 makes the three components all equal to the largest component, i.e. S : we thus obtain the wanted mapping of the initial picture saturation. Unfortunately, I am not sure this Photoshop model really is the HSV Affinity model, since when one moves the Luminosity slider the above RGB components do not change in agreement with the above formulas... But maybe that's another story!
  11. My file is a macro record ; you must import it in the AP macro ou library panel
  12. I return to the original post of dmstraker. Though the recipe looks somewhat sorcery, it really builds a grey picture with R=G=B=Max-Min where Max and Min are the largest and the smallest of the original RGB components, i.e. the genuine absolute saturation in HSL models. I wrote a script which performs this computation and I obtain exactly the same results. This script can downloaded at http://www.oitregor.com/numeric/affinity_photo/divers/selection_saturations.afmacro Of course, this does not yield saturation in LAB sense, but in practice this should have little consequence. I also wrote a script for chroma — SQR(a^2+b^2) — but I failed to convert it from Photoshop to AP.
  13. Hello I hope I attach the file you were asking for. The whole experiment is very simple luminance_selection.mp4
  14. I experimented with Granger chart (see picture –can be obtained with a superimposition of a "spectral " gradient (RYGCBMR) and a BW gradient in luminosity blending mode) in 8-bit, 16-bit or 32-bit mode. The so-called "luminance" selection as given by the shortcut CMD-SHIFT-click takes three different forms! Seemingly the luminosity concept would change when switching from 8-bit to 16 or 32-bit RGB mode: I can hardly accept that. 16-bit RVB ou 16-bit LAB yield the same results — though it could have been expected that the "luminance" selection in LAB mode would be the true LAB luminance selection. Only the 32-bit result seems to stick to the expected result, namely true LAB luminance selection. I attempted to look at possible changes in the 1.7 beta version but I was unable to locate the "Document > Color Format" menu.
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