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p.1 #17 · p.1 #17 · NEC PA272W calibrated for Bay Photo having difficulties | |
dgdg wrote:
... If V4 profile were causing me an issue, what would I notice?
In most cases apps either work with V4 profiles or don’t work at all with them. For example the 3D gamut viewer at ICCView.de simply will not accept them. In a small number of cases there have been reports of color casts, and other problems, but it is often difficult to pin it down to V4 profiles solely, since switching to V2 means switching to another profile, so it may not be the version, but something else in the profile.
There were cases of V4 profiles from Canson causing very light blue/gray in the borders of prints, but only on the Mac OS. The same V4 profiles didn’t cause problems running under Windows.
I don’t know of any software that currently makes use of the extended utility of V4 for paper/printer/ink profiles, so you are getting nothing more out of them than you would from V2, and V2 works and V4 sometimes causes problems. In short you gain nothing from V4 until there is more support for them, and you risk problems.
Since V2 color space profiles don’t support lookup tables, they are simple matrix based profiles, then conversions from one color space to another are always done calorimetrically. For example, a conversion of an image from ProPhotoRGB to sRGB for web viewing, would in Photoshop always be done calorimetrically, even if you select perceptual; there isn’t enough information to do otherwise.
I haven’t checked Photoshop to see if it makes use of V4 so that perceptual rendering is done for working space conversions, but last time I looked the ICC had released a V4 sRGB profile, but I don’t think anyone has released a V4 ProPhotoRGB profile. Adobe may have a released a V4 AdobeRGB, but I haven’t checked their profile page recently.
[And just because a space profile is V4, doesn’t mean it contains the two perceptual LUTs. It is only an option in V4.]
Brian A
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