2026-10-09 APP 2.0.0-beta48 has been released !
This is mainly a bug fix release for the reported bugs in beta47. In addition it has a significant User Interface performance improvement noticable when you need to process 1000s of images in APP.
2026-10-03 APP 2.0.0-beta47 has been released !
This is a very big release... many code optimizations/rewrites, many parts of APP are much faster and more precise, especially star analysis and registration are much faster ! Big mosaics will go much faster 🙂
And we introduce a new preview filter, which includes the new Adaptive Deep Sky Stretch and a General Levels Stretch, this has been long over due. The old preview filter (the panel on the right side to stretch and preview your data) has not been updated for a couple of years and it is a critical part of any APP session.
Adaptive Deep Sky Stretch or ADSS is a much more intuitive stretch algorithm. It is also color preserving (which is a great new addition in itself ! ) which means that the highlights are no longer bleached, color is maintained from the linear data while stretching. You can simply stretch your data using the sky background level and signal width sliders which work much easier and more intuitive. You no longer need to fiddle with the old complicated sliders with zoom buttons. All the zoom buttons for the sliders are made redundant. And you can enter slider values in the slider value fields yourself. I will make a youtube video in the coming days to explain and fully introduce ADSS. Once the video is ready, it will be highlighted on the forum.
RGB Combine upgrade !. The RGB Combine Tool has been rewritten mostly. The tool is faster and easier to use and most importantly, the Luminance slider to inject a luminance channel or channels into the RGB composite is now working correctly. It no longer bleaches the RGB colors. Combined with the new ADSS preview, you will get much better and easier great composites with great color! I will also explain this in a new youtube video.
When you save an image in TIFF, PNG, JPEG format, you can specify a color space, such as sRGB. I am wondering how this is done. I expect APP just to set the chosen color space, and not do anything to the image itself. But it could be possible that the color space of the input files is used, eg, when you import DSRL RAW's.
Reason I am asking is because it appears to be possible to map emission line wavelengths to RGB colours in a color space, for instance: https://stackoverflow.com/questions/3407942/rgb-values-of-visible-spectrum/22681410#22681410. Â
Hi Sander, @svdwal
If you save an image with a color profile, an ICC profile is attached to the metadata which holds information for other applications so they can present the data in that way while respecting that color space.
When the ICC profile is applied to the metadata, there is a color convert operation done on the data so the data does change. This is needed for color management to work properly.
The color space of an input images does not apply nor is used nor is it relevant. The RAW images have linear RGB data, the metadata that says it might be sRGB or Adobe1998 for instance is just for image viewers to be able to show it in that color space in it's non-linear representation. The RAW data is simply the non-converted data, so you could present it in any color space as you want or need to 😉
As you could read in the mentioned topic on stack overflow, it is not a simple task to convert a visual wavelength to a specific 8bit RGB color... but yes you can get there of course. But I must point out, this is something completely different than color management in which you try to maintain the colors that you have on your computer screen and save it with an ICC profile, so another application on your computer and monitor will show the data exactly the same...
Color management takes places on many levels and is not an easy subject. The software needs to be able to do it. Then your computer monitor needs to be able to show that color space. Most monitors can only show sRGB fully... so using a color space like Adobe 1998 is not very usefull for many because their monitor can't show it properly. And then you still need to make sure that the monitor is well calibrated... if it is not, things will probably not look correct...
Mabula
Thanks, Mabula. I am aware of some of the issues, and will run into some of the other ones too.Â
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I have a better link, with a theory and accompanying Python code: http://www.markkness.net/colorpy/ColorPy.html
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