Legacy ImageMagick Discussions Archive

Hi!

I'm new to image processing in general, and newer working with ImageMagick. Thus, I lack the right vocabulary and skills even to ask here! So, please, excuse me if my question is too basic. I'm working in Mac OS X Leopard and Snow Leopard boxes.

I've being done bunch of tiff images from which I've to create web versions. Here an example:

http://ftp.ebiotic.net/onPdr/polboCropped.tiff

If I open any of this images with Mac OS X preview, I see it correctly. Something like this...

http://ftp.ebiotic.net/onPdr/polboCropped.jpg

If I use ImageMagick to see it (display polboCropped.tiff), I get this two errors:

display: incorrect count for field "MinSampleValue" (1, expecting 5); tag ignored. `polbo' @ warning/tiff.c/TIFFWarnings/704.
display: incorrect count for field "MaxSampleValue" (1, expecting 5); tag ignored. `polbo' @ warning/tiff.c/TIFFWarnings/704.

And see this...

http://ftp.ebiotic.net/onPdr/polboCropp ... isplay.jpg

If I save it, I won't get the errors again, but get the same image.

If I use Preview to convert the image in tiff format to jpg, I get a black/white picture... I don't know what is the problem here.. Something related to the Alpha channel?

Please, how could I convert these tiff images to jpg or png to diplay it in a website?

Thanks for your help!

I am not the expert on TIFF files, but your tiff file is in CMYK and has an icc profile, which I presume is CMYK.

In general to display it correctly, you need to convert it to RGB with profiles. So in unix IM, you would do

display -profile Profiles/sRGB.icc polboCropped.tiff

which seems to work fine on my Mac OSX Tiger using IM 6.6.4.7 Q16

I have stored my profiles in a directory called Profiles, but you can put them anywhere, just provide the path to them.

You can also convert the image from CMYK to RGB

convert polboCropped.tiff -profile Profiles/sRGB.icc polboCropped_rgb.tiff

Search your Mac. You should have icc profiles already there. But you can find some (profiles.zip) at http://www.imagemagick.org/download/delegates/

For newbies, good reading is at:

http://www.imagemagick.org/Usage/

Thanks! I must read and use what you have propossed but I am already able to convert flles to RGB (using http://www.color.org/srgbprofiles.xalter profiles).

Cheers!

Forgot to mention this link on using profiles in IM. see http://www.imagemagick.org/Usage/formats/#profiles

Hi!

After reading and struggling with my group of files I've found that what was sent to me as a "uniform" set of files is formed by files of rather different characteristics. I've been only able to get an uniform output by removing the alpha cannel after flatten the backgroundo to white. It is enough for me now. I've learnt a lot and see how powerfull is ImageMagick and, even more, ImageMagick combined with Linux/Unix scripting facilities to process lists.

Let me past here a link to how remove the alpha channel for future reference.

http://studio.imagemagick.org/pipermail ... 18215.html

I think no single solution could be applied to all the files. That was what was making me nuts! I see that is possible to use ImageMagick to apply customized solutions based on the information stored extracted from each file, but this is out the scope of the current problem!

Thanks for your help!