Convert Mode and Scale

[Just Fred]

I need to do the following to all open tif images in Gimp.

change mode from indexed color to grayscale
scale image to half size (from 9912x7008 to 4956x3504 and resolution from 600 pixels per inch to 300)
save to xcf format using current file name plus a -300 suffix

I have a couple hundred files in 25 folders to do. Doing one at a time is slow going. Any way to speed up the process?

Thanks Fred

[Kevin]

Do you really mean you want to do this to images already open in GIMP? - I ask because you say you have "a couple hundred files", which implies you will be importing each of them into GIMP initially.

OR were you looking to do this in a headless way from a command line for example?

[Just Fred]

I don't need to open the images first in Gimp. Whatever method which would be quickest.

[rich2005]

Probably Kevin will come up with a script. Looking at what us lesser mortals can do with what is available, my tuppence worth.

The snag is the .xcf requirement. Using the command line imagemagick would be great except it does not write xcf files.

In Gimp there are 2 GUI batch plugins. BIMP and the old DBP Neither do the whole job but you could use one after the other.

BIMP does
Convert to grayscale
Resize and set the new 300 ppi
Rename with a -300 tacked on the name.

What it does not do is re-save in xcf format.

DBP (Davids Batch Processor) The bit that is missing from DBP is the 300 ppi requirement, but it does save as .xcf
After running BIMP to new files, run DBP on the new files with just the one option - save as xcf.

A quick test here with a half-dozen files is good. A bit of a round-a-bout but better than one file at a time.

Question - Are you really running WinXP and what is the Gimp version you use?

[Just Fred]

Thanks Rich. BIMP works perfectly. I just converted to png instead of xcf.

I have several computers and yes one is still a XP machine. The others are dual boot Win 7 and Linux Mint. I'm running Gimp 2.8.10

Fred