Flat value with 460ex color

[sunburst78]

Hi

I'm just stepping out of the DSLR world and I had a question about flats. I've read that flats should have a pixel value of about 20,000 - 25,000. The problem is if i were shooting in mono that would be easy because I'd only see one value per pixel in Dawn but color images give me 3 totally different values per pixel... which value (R,G, or B) should I be using to get close to that 20,000 ish number?

Thanks in advance.

[chrisjbaileyuk]

I find it is very easy with the 460OSC to overcook the flats so I tend to keep all three peaks well below the 20,000 mark, on mine the highest peak is around the 16,000 mark.

[sunburst78]

Will do. That means Red would be 16,000+- followed by green and blue. The difference between the 3 is rather large so it threw me off. Thanks again.

[chrisjbaileyuk]

I have found that if you put the lowest peak at or near the 20,000 ADU mark, the flats overcorrect and if I expose for the normal advice of putting the histograms around the 30,000 mark the results are unusable. Putting the red at 16,000 or so the flats correct very well indeed even though the other peaks are down at ~12,000 and 8,000. Took a lot of experimentation!