Convert 32-bit to 24-bit while maintaining 2400x2400 pixel size and 72-dpi

[ekoenig61]

I am creating an image for Amazon for a CD sized case. It has to be 2400 x 2400, at least 24 -bit, no less than 72 dots per inch. The big problem is that it has to be under 8mb. Png, tif or jpg. I have created this in Photoshop and fought with all sorts of different save techniques and managed to get it down to 13 megabytes in TIF format. Adobe help says it is easy to do in Elements, but I don't have elements and really don't want to purchase it for just this one project. Any ideas out there? How to even move this from 32 bit to 24-bit and maybe that brings down the size from 13 megabytes to the required 8 megabytes. Any ideas welcome!!

[D Fosse]

If it's 8 bits per channel RGB, then it's 8 x 3 = 24 bits. If you have an alpha channel in there, it's 8 bits more = 32 bits.

An uncompressed 8 bit TIFF at 2400 x 2400 pixels will be roughly 17 MB.

So you need to compress the file. If the TIFF compression options aren't reducing the size enough, you may need jpeg or PNG. Jpeg compression is the most effective; it should get this well under one MB - but at a price. Jpeg compression is destructive and non-reversible, and it will introduce artifacts that can be visible, particularly if you have text.

Ppi, pixels per inch, is irrelevant for file size. It's just an instruction for physical print size by defining a pixel density on paper. The file is just pixels, and pixels have no size. Dots per inch is the wrong term to use for an image, that refers to ink dots on paper which is unrelated and something else even more irrelevant. Yes, lots of people use this incorrectly.