Getting image ready for print

[unifant]

Hi folks,

i couldn't find any help by searching for my problem.

I have resized and croped an image. The size of this image is eg 800 x 600 pixels.
When i open this image in Photoshop, it shows me
Pixel dimensions 800 x 600 pixels
And document Size 28,22 x 21,17 cm (11,111 x 8,333 inches) at 72 dpi resolution.

Now i want to get this image to document size 40 x 30 cm. The resolution will shrink to 50,8 dpi (thats normal).
In Photoshop i can do this easily, but i don't get it run with Imagemagick.
I tried '-resample 50.8x50.8' and '-density 50.8' but it doesn't solve my problem. With identify -verbose i get the resolution 51 but when i open it in Photoshop, nothing changed.

What can i do to get the size to 40 x 30 cm. I need this, to get the image ready for print, without manualy change in Photoshop.

My Imagemagick version is 6.5.4-8 2009-10-24 Q16 on SuseLinux 11.2

Thanks a lot
Yasin

[fmw42]

If your image is now 800 x 600 and you want it to print at 40x30 cm, then you need to set the density to 20x20 in units of pixelspercentimeter. But not all formats support that unit.

density = 800/40 = 20 and 600/30 = 20 pixels per centimeter

convert image -density 20 -units pixelspercentimeter result

Otherwise, you need to convert the density to units of pixelsperinch

40cm/2.54cm per inch =15.75in

so in units of pixels per inch

800/(40/2.54) = 800*2.54/40 = 20*2.54 = 50.8
600/(30/2.54) = 600*2.54/30 = 20*2.56 = 50.8

convert image -density 50.8 -units pixelsperinch result


see
http://www.imagemagick.org/script/comma ... hp#density
http://www.imagemagick.org/script/comma ... .php#units

[unifant]

Thx, for supporting me!

Now i want to give back my result.

I have converted my photo exactly with the same command before. But nothing changed.
Today back again at work i tried something and it was very suprising.
When i open the image in photoshop it seems that nothing happened, it shows the same dpi like before.

Today i opened the image in the proofing software for my epson printer and it shows the image with the correct result.

It seems that photoshop has got an other meta-information that is not set. If some has knowledge about this, i think it will be helpfull, but my problem is solved.

I hope this will help others too, and thanks a lot again.

[jpiquemal]

Hi
Photoshop is probably reading the EXIF infos.

[unifant]

Hi,

is there any way to change the EXIF data of the imagefile?

Greets

[fmw42]

try exiftool at http://www.sno.phy.queensu.ca/~phil/exiftool/

don't know if it will let you change those values