Re: [Gimp-user] Compatibility with PS?

[Elle Stone <ellestone ninedegreesbelow com>]

On 10/29/2017 06:06 PM, Jeffry Killen wrote:
> Will Gimp open ps files: yes (which versions and what aspects are retained?)

I don't know which versions of PSD files GIMP can open. I do have some 
old CS2 PSD files that I recently spent some time opening with GIMP, 
after having not looked at them for many years.

I use GIMP 2.9, which is the development version of GIMP. Recently there 
have been quite a few new commits to the GIMP code that affect reading 
PhotoShop files. So the following observations are based on GIMP 2.9 and 
PhotoShop CS2. Hopefully someone else will chime in if I made mistakes 
in my observations or left out something important:

You will not be able to open a PSD file and continue editing "just as 
if" you were still using PhotoShop.

GIMP doesn't yet have adjustment layers (Curves, Levels, etc). Even if 
GIMP already did have adjustment layers, that doesn't mean GIMP would be 
able to interpret PhotoShop adjustment layers.

The only actual layers that GIMP can show when you open a PSD file are 
image layers, not adjustment layers. So if your PSD file has one image 
layer at the bottom, and a whole bunch of adjustment layers, then the 
only thing GIMP will retain when you open the PSD file is the image 
layer at the bottom.

So if your computer on which PhotoShop is installed is on the verge of 
not working any more, it might be a good idea to open your most 
important PSD files and use the equivalent of GIMP's "make new from 
visible" to have a record of the result of intermediate editing steps 
that involved adjustment layers.

Also, if you want to use DAM software such as digiKam and you want to 
see a thumbnail for your PSD files, save your PSD files using 
compatibility mode. Back when I used PhotoShop, at some point I stopped 
using compatibility mode and now I have a lot of PSD files for which 
digiKam and Gwenview can't show thumbnails. Again, this is for CS2 - I 
don't have a clue whether CS4 even has compatibility mode.

GIMP doesn't have the ability to play PSD macros (I hope I'm remembering 
the right word). So if your workflow depends heavily on macros, well, 
you can learn to script in GIMP, but there will be a steep learning curve.

GIMP doesn't yet support opening, editing, and saving images in the LAB 
or CMYK color spaces. So if you have any important LAB or CMYK PSD 
files, it might be a good idea while your computer is still running to 
save a copy of these files after converting them to RGB.

Many of the layer blend modes are the same in GIMP and PhotoShop, and 
many are not.

CS2 is pre "smart layer" - is that the right word? so if you used that 
functionality, maybe someone else knows if/how GIMP interprets these 
types of layers. But again, for your important PSD files it would be a 
good idea to use the PS equivalent of "make new from visible" to have a 
record in the PSD file of what the smart layer was supposed to do.

If you find that you simply don't want to edit images without using 
adjustment layers, Krita might work for you better than GIMP. Even 
though Krita is primarily aimed at painting rather than photography, 
people do use Krita for editing photographs. I'm not sure how good 
Krita's support for PSD is. I tried opening a couple of files with Krita 
and the only layer that "survived" was the bottom layer, but I think 
this might be because of some system issues I'm having with KDE image 
file format support.

GIMP is not "free PhotoShop" and your best bet is to approach GIMP for 
what it is, on its own terms. Personally I much prefer GIMP 2.9 over 
PhotoShop CS2. I never used GIMP 2.8 except to prepare files for 
uploading to the web, because 2.8 doesn't support high bit depth editing.

Best,
Elle