Yes, forget bitmap mode. Keep it grayscale. I am presuming that you mean bitmap MODE (which is not a grayscale) rather than bitmap FILE FORMAT (which may be a grayscale).
Then he will want to know how to color the file in Illy…
The trick there is to place the grayscale in Illy then make an unstroked box containing whatever color you want to color the photo with. Make that box the same size/position as the grayscale, send it to the back, then select both the box and the grayscale and make an opacity mask via the transparency flyout (making sure that "new opacity masks are inverted" is selected).
Otherwise, you can always convert your Grayscale to a color mode in Photoshop and Adjust>Hue/Saturation>check "colorize" and play with the sliders.
The reason you don’t want use Bitmap is because it’s a binary form…meaning that a pixel is either black or white. There’s no gamut, simply a "Yes" or "No" regarding each pixel.
Grayscale allows shading of each pixel.
Guys,
Thanks a lot. I found a good solution for my problem within your replies. Regards,
Laith