View Full Version : working with 1 bit or 4 bit bmp in photoshop 7


soibaal
05-21-2006, 11:25 PM
Hi friends

I have a bmp file which when i open in windows paintbrush appears colored. when i open the same bmp file in photoshop 7 it appears black and white. plz help me to open a bmp file in photoshop 7 as in paintbrush.

This bmp file's link is http://www.geocities.com/soibaal/bmp/

i believe photoshop uses minimum 8 bits/channel and this bmp file was changed to less than that may be 1

bit/channel so it shows only 2 color black and white.

My requirement is to reduce this bmp files dimensions. But it would be of no use if it is in black and

white.

i dont know how to work with 1 or 4 bits bmp file.
plz help me. this is very urgent.

I would really appreciate this.
thanx a million.

have a nice day.

soibaal

Doug Nelson
05-21-2006, 11:33 PM
Photoshop can handle 1bit files just fine, but a 1bit file can only display black or white, nothing else. So if you're seeing it with any other colors, it's not a 1bit file, or the color is coming from xml data. Not that this helps your problem.

It might be faster just to replace the color than to spend time trying to learn why.

Old Canoeist
05-22-2006, 06:02 AM
Opening the file in PaintShopPro 7, I see the file in color. Colors>Decrease Color Depth Shows no decrease possible while Increase Color Depth shows 4, 8 and 24 bit available. The color gamut diplay shows just two colors - yellow and purple and the color picker indicates these are 255,255,0 and 255,0,255.

It is a 1 bit colored file.

Doug Nelson
05-22-2006, 12:12 PM
Some interesting things about the BMP format:
http://atlc.sourceforge.net/bmp.html

It seems you have a 1bit file with a header that describes how the 0 and 1 states should be displayed. This is a holdover from the OS/2 days. It appears Photoshop doesn't support the header and displays the 0 and 1 states in their native state (black and white).