AusAlmond
Member
I have used Roger Clark's Color Stretching software for some years. I shoot at low ISO on my Sony A6400 to preserve the brightest stars. I then stack 2-4 hours of 30 second stills with DSS 64. This avoids many problems including bad frames, needing a guiding system and bypasses known Sony issues with Bulb mode.
Stretching doesn't always work because the software seems to need a bit of level to process. Using GIMP I apply some curves to the stacked image to get the brightness up and it works some of the time. When it does, results are amazing. While I understand some of what is happening and can achieve quite good results with GIMP alone, the stretching software is much easier and more importantly repeatable.
Sometimes however it doesn't work and it complains that the data format is wrong. I submit 32 bit floating point TIFF but it doesn't always recognise that. I've compared the headers between those that work and those that fail. I found that the more complex headers fool the software and it's not easy to fix. Editing headers by trial and error using exiftool is hard.
Today I found that version 1.02 of RNC Color Stretch has been released. Testing it on some of the failed files shows that the input format handling seems to work more consistently and I think that the overall quality of the images produced is even better.
If you use this program, I strongly recommend getting the update. Thanks Roger Clark.
Stretching doesn't always work because the software seems to need a bit of level to process. Using GIMP I apply some curves to the stacked image to get the brightness up and it works some of the time. When it does, results are amazing. While I understand some of what is happening and can achieve quite good results with GIMP alone, the stretching software is much easier and more importantly repeatable.
Sometimes however it doesn't work and it complains that the data format is wrong. I submit 32 bit floating point TIFF but it doesn't always recognise that. I've compared the headers between those that work and those that fail. I found that the more complex headers fool the software and it's not easy to fix. Editing headers by trial and error using exiftool is hard.
Today I found that version 1.02 of RNC Color Stretch has been released. Testing it on some of the failed files shows that the input format handling seems to work more consistently and I think that the overall quality of the images produced is even better.
If you use this program, I strongly recommend getting the update. Thanks Roger Clark.
