Well, that's the extent of my guessing. Somebody else? On Thu, Aug 7, 2008 at 1:08 AM, Rohan. Kurian <[EMAIL PROTECTED]>wrote:
> Thanks Ross. Your explanation clears up things. However as far as doing > a resizing or something in order to change depth, I don't think it's right. > You can change depth > > Alone. > > I took an 8-bit RGB jpeg image and changed it to 16-bit in photoshop. > > Consequently, it was much bigger in size. When I ran identify on the image > it still showed the depth as 8-bit. > > Either ImageMagick doesn't supoort any other depth other than 8 or the > identify program is flawed or may be > > Something else. > > > > *Some ops on the jpeg images* > > C:\Program Files\ImageMagick-6.4.2-Q16>identify Room_King.jpg > > Room_King.jpg JPEG 644x446 644x446+0+0 8-bit DirectClass *38.4kb* > > > > C:\Program Files\ImageMagick-6.4.2-Q16>identify 16Room_King.jpg > > 16Room_King.jpg JPEG 644x446 644x446+0+0 8-bit DirectClass *81.5kb* > > > > C:\Program Files\ImageMagick-6.4.2-Q16>convert -size 10X65500 gradient:blue > -dep > > th 4 16Room_King.jpg > > > > C:\Program Files\ImageMagick-6.4.2-Q16>identify 16Room_King.jpg > > 16Room_King.jpg JPEG 10x65500 10x65500+0+0 8-bit DirectClass 6.5kb > > > > I then converted the jpeg to tiff and then ran the operations on it. *Here > I was able to change the depth without doing any resizing operation or > anything*. > > *Some ops on tiff* > > C:\Program Files\ImageMagick-6.4.2-Q16>identify Room_King.tif > > Room_King.tif TIFF 644x446 644x446+0+0 8-bit TrueColor DirectClass 863kb > > > > C:\Program Files\ImageMagick-6.4.2-Q16>convert -depth 16 Room_King.tif > 16Room_King.tif > > > > C:\Program Files\ImageMagick-6.4.2-Q16>identify 16Room_King.tif > > 16Room_King.tif TIFF 644x446 644x446+0+0 16-bit TrueColor DirectClass > 1.652mb > > > > C:\Program Files\ImageMagick-6.4.2-Q16>convert -depth 8 16Room_King.tif > 8Room_Ki > > ng.tif > > > > C:\Program Files\ImageMagick-6.4.2-Q16>identify 8Room_King.tif > > 8Room_King.tif TIFF 644x446 644x446+0+0 8-bit TrueColor DirectClass 849kb > > > > *Then I tried converting the tif to jpg, hoping it might work (No luck)* > > * * > > C:\Program Files\ImageMagick-6.4.2-Q16>identify 4Room_King.tif > > 4Room_King.tif TIFF 644x446 644x446+0+0 4-bit TrueColor DirectClass 428kb > > > > C:\Program Files\ImageMagick-6.4.2-Q16>convert 4Room_King.tif > 4Room_King.jpg > > > > C:\Program Files\ImageMagick-6.4.2-Q16>identify 4Room_King.jpg > > 4Room_King.jpg JPEG 644x446 644x446+0+0 *8-bit* DirectClass 59.7kb > > > > > > Thanks again, > > Rohan > > > ------------------------------ > > *From:* Ross Presser [mailto:[EMAIL PROTECTED] > *Sent:* Thursday, August 07, 2008 2:18 AM > *To:* Rohan.Kurian > *Subject:* Re: [magick-users] Unable to change depth > > > > Your original image is 8 bits per channel (24 bits per pixel). It has a > maximum of some 16 million colors. If you're not resizing or transforming > the image in any way, the output cannot need more than 16 million colors. > Therefore when it is saved, it still only needs 8 bits per channel, and so > it is saved in that format. > > Furthermore, I'm not sure you can have 16 bits per channel in a JPG. I > tried these: > > C:\TEMP>convert -size 10x65536 gradient:blue -depth 16 foo.tiff > C:\TEMP>identify foo.tiff > foo.tiff TIFF 10x65536 10x65536+0+0 DirectClass 16-bit 5.00521mb 0.094u > 0:01 > > C:\TEMP>convert -size 10x65536 gradient:blue -depth 16 foo.jpg > convert: Maximum supported image dimension is 65500 pixels `foo.jpg'. > > C:\TEMP>convert -size 10x65500 gradient:blue -depth 16 foo.jpg > C:\TEMP>identify foo.jpg > foo.jpg JPEG 10x65500 10x65500+0+0 DirectClass 8-bit 6.56445kb 0.094u 0:01 > > > On Wed, Aug 6, 2008 at 7:03 AM, Rohan.Kurian <[EMAIL PROTECTED]> > wrote: > > I have to meet a requirement where I should be able to change the image > depth. > > I am using ImageMagick-6.4.2-Q16 on Windows > > I have tried to convert 8-bit images to 16-bit/4-bit images but haven't > succeeded. > > identify Room_King.jpg > >Room_King.jpg JPEG 644x446 644x446+0+0 8-bit DirectClass 38.4kb > > convert Room_King.jpg -depth 16 16Room_King.jpg > > identify 16Room_King.jpg > > 16Room_King.jpg JPEG 644x446 644x446+0+0 8-bit DirectClass 39.5kb > > > What am I doing wrong? Can I not convert from 8-bit jpeg to 16-bit jpeg? Am > I using the command in an erroneous fashion? > Any input would be appreciated. > > Thanks, > Rohan > _______________________________________________ > Magick-users mailing list > [email protected] > http://studio.imagemagick.org/mailman/listinfo/magick-users > > > _______________________________________________ Magick-users mailing list [email protected] http://studio.imagemagick.org/mailman/listinfo/magick-users
