Maddening color shift upon jpeg conversion and downsize. If anyone knows how to compensate, please share. From a ~4 frame stitch.
Hi David,
If you are doing this through PS with a stack of layers that are utilising a variety of different blend modes to produce the image you see on screen, which I think may be what you are doing, then all sorts of weird things can happen to the final shot when you flatten the image in one go. Don't know why PS does this (sometimes), but I can only guess that the Adobe code writers might have thought that different blend modes should get processed in an order of preference, you know like mathematical operators or something and which may not then suit the order in which you have processed your image and stacked your layers. In other words it might render an upper layer mode first before the one below it and so on and which can then change the overall effect in the fully flattened image - but as I say, I am only guessing here.
When I occasionally get this problem, what I usually do is to duplicate the background layer, then select this new layer and all the other layers above it, then flatten only these selected layers into a single layer while leaving the background layer alone, then if it works, I then a flatten the image completely. If this doesn't work, then you could try the more long wided method, that is when you have finished processing your file but with all the layers still intact, you could then try stamping each layer effect into a new layer as you work up your layer stack one by one, which again sometimes works. Do this by turning off all your layers except your background layer and the one above it, then highlight the upper visible layer and then press (Ctrl+Alt+Shift+E) to stamp them into a new layer, then turn on the layer above it back on, highlight it and do the (Ctrl+Alt+Shift+E) thing again and so on all the way up the stack.
If this doesn't work, then I am just reading online that you can also try setting your cache levels preferences down to 1, as the on screen preview is then only ever based on the the full image data at that time, so you won't see any shift when finally flattening to a JPG, but may also mean you will never see the effect that you want to keep and I imagine it could also seriously slow down your machine, as it will have to generate a full screeen preview each and every time you do something new to the file.
Hope this helps
Oh and if you are using LR and your problem has nothing to do wit PS, then even though LR does not use layers (I think, as I don't use LR myself), then I also assume it uses something similar to a layers type of coding in the background for each step that you take, and if so then that could also cause a shift in colour etc when you export it as a flattened file out to a JPG, due to how it chooses to prioritise and render each effect etc, but I am really only guessing even more now and so as far as LR goes, I am afraid haven't got any suggested work arounds sorry.
Perhaps one of the 'in-the-know' people on here such as Jeff Schewe might be able to help here, as I really would like to know why PS does this (but only occasionally) and how to overcome it when it does, although my rough workarounds mentioned above do seem to sometimes to do the trick, but not always...
Dave
