Master Flat displays all cyan? (DSLR)

Posted by: @chrisl

Hello,

my name is Chris, I am new to APP an allready stacked a few Deep Sky pictures with it.

Hi Chris and welcome to the forums!

I am using a Nikon D750 and I convert the RAW-files with Nikon's Capture NX-D into TIFF before loading the files into APP (reason being the "noise reduction for Astro photos" feature of Nikons converter eliminates all bad pixels and also reduces residual colour fringes arround stars).
I am doing this also with all other frames (all correcion frame exposures).

So, my advice; don't do that. 😉 The reason is that APP is made specifically to do that work for you, it has very advanced algorithms made specifically for astro-photography and is able to correct these things in a much better way (almost always), then general processing tools. These tools, more often than not, actually degrade the image quality. You need to use darks and bias calibration frames for APP to do this and load in the RAW files directly into APP.

The 25 flats are integrated in APP "average", multiply-scale, BWMV, no blur, no rejection, noLNC.

When you use 1.079 and onwards, you can just leave the options on automatic and APP will choose the correct settings for you.

So could you try to test this with 1.079 and loading in the raw data? Load in the flats and bias and let it calibrate automatically to see how that looks like.

Vincent,

thanks for your quick reply!

Yes, I was using Version 1.079. I will try directly loading in the NEF-files.

Maybe my flats are flawed, since the histogram of the Master flat shows clipped red and almost saturated blue.

Chris

This is happening to me as well with my Flats.  When I load a single or even the Master Flat APP asks to which channel to assign the frame.  What is the correct answer there?  I seem to always get an all Cyan colored screen with no actual Flat frame artifacts.  Unsure of how to proceed.

Dale

The flats should be applied to the session that they were meant for. Usually you take flats after every session.

The strange color artefact, not sure, what happens when you switch off normalization on the right panel and stretch?

Vincent,

When I load a Flat or Master Flat after checking "Force Bayer CFA" and selecting a pattern for the Sensor in 0) Tab, the pattern is mostly Cyan.  There are details from the Flat visible, but faint.  When I tick the neutralize BG, all the ugliness reveals itself.  It almost looks like a rectangle vignette.  What can I make of this?  And, if the Flats are being extracted from the Integrated file, why does all of this mess show up in the end result of Integration?  I'm baffled.

Thank you,

Dale

Vincent,

Here are the Screenshots.

Mmm, that might be a flat issue. I see you're exposing for a very long time, is this due to a narrowband filter perhaps? How exactly are you taking the flats?

For a proper preview, switch off the DDP as well as it shouldn't be stretched then.

I am new to the forum and have another post not exactly related although I can vouch that my flat screen is the same cyan color.  All of my files come from the ASIAIR file structure which gets this from my Nikon D5300.  No manipulation has been done to the file.