I have a number of images with aspect ratios varying from 10:8 down to 10:5. I want to send these for commercial printing on 12x10 paper with a 1" border on each edge to allow for mounting.
How do I produce a final picture at 12x10 with an appropriately sized border? I normally use DarkTable for image processing but I am up for any other piece of software provided the final image retains the embedded destination paper colour profile.
12x10 (inches?) with a 1" border = 10“x8”.
Assuming you want a pixel density of 300PPI, 10*300 x 8*300 = 3000 x 2400.
Your photos should not be larger than that.
In RawTherapee you would set the resizing tool to “bounding box” and set the bounding box width to 3000px and height to 2400px.
I don’t think I have explained myself too well. I need to supply a canvas that is 3600x3000 pixels in size with an image that is between 3000x2400 to 3000x1200 in size centred on the canvas.
In DarkTable I can specify a border that is a percentage of the image size but as far as I can see there is no way to do the above.
I can do it in the Gimp (version 2.10) by setting a canvas size and centring the image on this but it doesn’t look as though it retains the colour profile of the paper.
Then this is a colour management issue. What are you doing when you open your image in GIMP?
I open the raw image in DarkTable, manipulate it then export it as JPG with the output profile set to that given to me by the printers.
I then open it in GIMP, set the canvas size to 3600x3000 and centre the image on the canvas. I then overwrite the JPG file.
Do you get a dialog asking whether you would like to keep or convert your colour profile? If not, you might not have colour management on.
Nobody suggested ImageMagick ?
I don’t think I have explained myself too well. I need to supply a canvas that is 3600x3000 pixels in size with an image that is between 3000x2400 to 3000x1200 in size centred on the canvas.
Are the images already that size? Can be scaled in the command line, however keeping it simple.
A 3600x3000 @ 300 ppi white image 12x10.png, your photo.jpg @ 300 ppi, the icc profile from the printing company
convert -gravity center -composite 12x10.png photo.jpg -profile your-printing-co.icc out.jpgNot everyone is comfortable with command line. This would be the ImageMagick command that you could easily add to a script (which I will leave out because I don’t know your OS):
convert input_image.jpg -gravity center -background white -extent 3600x3000 -profile printer_profile.icc output_image.jpg
If you are using ImageMagick 7, replace convert with magick.
| Task | Option |
|---|---|
| open image | input_image.jpg |
| image position | -gravity center |
| canvas colour | -background white |
| canvas size | -extent 3600x3000 |
| output profile | -profile printer_profile.icc |
| save image | output_image.jpg |
PS I forgot to mention that you have to be careful with the -profile option. Read the manual carefully: ImageMagick - Command-line Options.
I don’t get a dialogue box asking for the output colour profile, though as far as I can see I do have colour management switched on.
No problems with the command line. I am a long-term Linux user.
Your suggestion works for me and I can script it for all the images that I want converted. Many thanks.
