I can no longer assign a spot color to a bitmap. Its not working in 26.4.1 and also not working in 25.4.7. I don't know for sure when this happened because I haven't needed to do this in awhile sot it might have been this way for a long time.
What file type is your bitmap image?
I think you can just save it as a greyscale image -- TIF format works for me
* the option to adjust the fill colour is in the Appearance pallet
It is working fine for me in 26.4.1
I checked with jpg files in bitmap mode and grayscale.
I also tried one in BMP format -- still worked fine.
Check the color space of your placed file to make sure it is actually in bitmap or grayscale, and not an RGB or CMYK file that just appears to be a bitmap.
bmp is the problem for me. Grayscale will take a spot color with no problem. I can import a bitmap or just draw a circle and convert to bmp and it won't take the sopt color. Hmmm. But its working for you so there must be something on my end.
OK I see the problem now. When converting to bitmap, it has to be "transparent" in the settings. White background won't work. Maybe I just forgot these details but something else seems new to me. Maybe I was wrong again, but I thought that if I did a "select all", copied a bitmap (bitmap mode) from Photoshop and pasted it into Illustrator, it would have the white background. But now, I see that it doesn't. When I paste it into Illustrator the background is transparent. Maybe I didn't notice that all these years. Anyway, thanks for the help everybody. I'll have to be careful. I assigned a black color to a black and white bmp in Illustrator, thinking that it was fine but it wasn't. When you select the image, the color palette selects the spot color so it really look like the color is assigned properly. When I do preflight, that image is not assigned with the spot color.
If you are in Photoshop's Bitmap mode, the white background will become transparent when saved as PSD, TIFF, or BMP and placed in AI or ID. Personally, I use an LZW-compressed TIFF file to keep the file small; I hardly ever use BMP.
You can also use Edit > Edit Colors > Convert to Grayscale after placing the image embedded and apply the spot color.
Yeah, I've used Convert to Grayscale before and it works. But when I have the opportunity to make the file size as small as possible, I'll use the bitmap type inside Illustrator rather than grayscale. I don't know if Convert to Grayscale makes the file size bigger or not.
Just a note about grayscale v. bitmap mode
A high-resolution bitmap mode image* can look like a vector graphic; grayscale images will look like a photograph-type image.
*As mentioned, I save as LZW-compressed TIFF
Yes, but a bitmap converted to grayscale in Illustrator will still look like a bitmap.
Unless you are delivering a PDF and use grayscale down sampling. (Viewed at 400%)
Yes, but downsampling bitmaps are also not a good idea. But I have never used BMP. Always PSD or TIFF for bitmaps.
I would disagree with the downsampling statement. If done properly, it can greatly reduce unnecessary resolution. My example was a TIFF--I never use BMP either.
I appreciate the info. But we're talking about different things actually. I've sorted it out now, but I was talking about actual bitmap images. Like, if I drew a circle in Illustrator and turned it into a bitmap then tried to assign a spot color to it. The problem was that I guess I forgot that it needed to be "transparent" in the settings. A bitmap image with white background does not allow a spot color assignment. That was my issue.
Seems to work fine for me in Illustrator 26.4.1
How are you creating your Bitmap file?
Are you using Image>Mode>Bitmap or just saving straight to BMP ?