I have been having a very hard time processing my Ha/Oiii/Sii data from my heart nebula session. I am using APP for multi channel integration, then at the end I am using RGB combine to create the color image in the SHO hubble palette. I end up with a very noisy image and the background seems very blown out. My first major question is...should I be editing each channel individually in APP before I combine the three channels? I see almost everyone editing the 3 channels individually on youtube when using other editing software.
Individual processing is indeed a good workflow as you can tweak each channel very precisely to your liking. Also take into account that you might need more data to reduce noise in specific channels. I normally create masters of each channel and process them as well as possible before recombining. After that, I do another light pollution correction.
I turn on multi-channel/filter processing and load in all light at the same time. APP will ask to which channel they belong and all will be loaded in correctly. I load in my master calibration files and assign them and then proceed to integrating them per channel. You get masters of each channel and you can go ahead and use some of the tools in tab 9 to process them further. LP correction, etc. Then you can use those results in the combine tool.
ps. do you have a mono or color camera btw? If you have color and use a filter, make sure to select the proper algorithm in tab 0. For instance, if you have an Ha-filter, select the Ha algorithm and APP will extract the Ha directly from the RGB lights.
Maybe the existing bug in the RGB Combine Tool in APP 1.075 is upsetting your results here with the RGB Combine tool. Have you tried the latest APP 1.076 beta3?
there was a bug in the RGB Combine tool as demonstrated in this topic: https://www.astropixelprocessor.com/community/main-forum/good-lrgb-stacks-show-up-as-very-dark-in-rgb-combine-tool-even-at-30-stretch/ This problem has been fixed now. The tool has been further improved with the option to choose how all channels in your composite are normalized with each other, just like in 5) Normalize. Previously, the frames were only normalized additively. Now, by default they are normalized with Multiply-Scale which is the recommend normalization when you are creating a composite using different filter data and of different sessions. The first image shows a bad composite result in APP 1.075 due to the bug, the second image shows the same composite in APP 1.076 where the bug is fixed and where better normalization has been applied:
It could very well be that the bug is creating the bad result that you are seeing, so please try with the beta release if you haven't done so 😉 and let us know the results.
