Copy the file before flatting it. Save the non (huge) flattened file before going to the copy. In the copy file flatten it and do a test print. If the test print works for you then you have your finished file.
The above is a small portion of my normal workflow. I also shoot with a IQ160 and can have huge files by the time I get to the point of printing. I'll save the working non-flattened file and copy it before I flatten the copy and print. If I like the print I'll only end up saving the copy as a good print or master print file and delete everything else. If on the other hand I need something else I'll return to the non-flattened file and tweak it....
Hope this makes sense. Also another reason my storage is measured in terabytes.
Don
One last thought is I always save as a Tiff as that is the most standard and should be readable for years to come.
Thanks all for the input. The file is 4.3GB, not 7 as thought before (not sure where I got that from; brain fade...). Still the same problem and one noted by many on the web, especially if the CC layers are different blending modes (normal, soft light, screen, etc.).
I think I do the same as you, Don. I will always have my saved master file with all the layers. I will then merge it (I usually use merge visible, but I tried merge flatten with the same result). Then I'll save the file with only the one layer as a .tif file.
When I do the merge in the master file, there is a definite change of contrast mainly. Perhaps saturation too, but it's quite noticeable. The part I don't do is a test print, which I think is a good suggestion, as that is what the final outcome is.
The web offers much advice, from taking the view up to 100% and ensuring the histogram has been "filled out" by hitting the triangle with the exclamation point before merging. Adding an empty layer on top of my pile-o-layers before merging, etc. etc. But the change still happens.
What I am doing now is tweaking the curve for a bit more contrast and painting a mask where the contrast isn't needed (clouds usually) on the .tif file after the layer merge. Gets me close, but sort of defeats the point.
I'll go to printing next and see how that works. Thanks for that suggestion. If yo or anyone else finds a different solution than yours and those given above let me know. You may want to try it yourself to see what I'm referring to. It may even happen with smaller files...
Thank you all!
Bob, whose storage is also measured in terabytes!