New Image question

[Marpel]

I am always generating (file>new>new image) a new, single colour, image which I use to blend/composite with an open image (48 bit colour - obtained from the camera) in the image window. It appears the new image "borrows" the same pixel size and resolution from the already selected photo, so I am presuming there is some relationship between the generation of the new image and the image that is already open in the window.

However, regardless of the bit depth of the current/open image, the new image is always 24 bit colour (out of curiosity, I also tried it with an 8 bit mask and a 24 bit colour image resulted). Is there a reason why the new image does not also "borrow" the colour depth? I see the dialogue has a drop down menu which gives the user a choice, however, it gets to be a pain always having to change this (and I often forget).

And, flowing from this - If the new image is 24 bit and part of it is comped into a 48 bit image (using a mask), I believe I read somewhere that it is automatically converted to 48 bit to match the original image, however, how does the initial mismatch affect the result if a blending mode like sift light, or other, is used?

Thanks,

Marv

[Marpel]

That's soft light, by the way, not sift light......

[jsachs]

In my experience, it is just as common to want to create a new image the same size as another image but of a different type (e.g. 8-bit B&W to match a color image).

In composite, 24-bit image data is converted to 48-bit before compositing with a 48-bit color image, regardless of the operation.

[jsachs]

Incidentally, you can composite with a solid color without creating a new image by setting the Overlay Image to the solid color you want to composite with.

[Marpel]

Thanks very much Jonathan.

I can accept the rationale for 24 bit default, and it's great to confirm the automatic conversion.

[jsachs]

I did ultimately decide to implement your suggestion for making the file type of the new image the same as that of the currently selected image.

[Marpel]

Excellent, thanks.