One of their standards is to make sure that the histograms are not clipped at either end, which for a lot of images is not a problem. Some images I've been working on today are a little more tricky, being into the light and as a result are quite contrasty.
I suppose you're supplying in RGB, and their concern is what happens to the highlights and shadows when the files are converted to CMYK
It did used to be a "rule" that you set your highlights no brighter than 245 and your shadows no lower than 30 (?) because in the pre-ICC days everything outside that range would most likely clip to pure white or block to pure black on conversion.
That would give you a histogram, when you exported to a TIFF, that wasn't clipped.
However at about the same time a myth grew that digital photography was flat and lifeless - and that was because the above technique could leave you with no sparkling highlights nor rich shadows - much like printing on too flat a grade of paper.
It's up to you if you argue the point with them, but my feeling is that if you can see shadow detail and highlight detail that's to your liking then the file's fine, whatever the histogram says, and it's up to the separators to hold that detail for their press conditions.
Kind regards,
Mike Russell =============================================================== GO TO http://www.prodig.org for ~ GUIDELINES ~ un/SUBSCRIBING ~ ITEMS for SALE
