8 Bit or 16 bit , sRGB or Pro Photo

Started Sep 11, 2019 | Discussions thread
technoid Senior Member • Posts: 2,276
Re: 8 Bit or 16 bit , sRGB or Pro Photo

I just ran another test with a gradient at 1" wide at 600 PPI from RGB 254 to 255 in 16 bits in Photoshop. It's surrounded  by a thin border so I could find it.

I then printed in in 16 bits using the highest rez settings possible on the Pro1000.

Next, I converted it to 8 bits in Photoshop making sure that the settings->color>dither option was off. This option dithers the conversions of 16 bits to 8 bits and I want RGB 255 on the left and RGB 255 on the right. Then I and printed it.

I can't see anything different unless looked at with a loupe where the light gray dots show up on the left half but not on the right halves of both prints.

The dots are sparse. To capture it I scanned it at 2400 PPI.  To enhance visibility of the light-light gray dots the image contrast was increased.

As you can see, the "16" bit print shows exactly the same pattern as the 8 bit one and it looks like it just rounds the 16 bits to 8 bits exactly the same as converting the image to 8 bits does.

Since the forum doesn't allow posting of 16 bit tifs, I can't post the originals used to print these but they are easy enough to create in Photoshop with the gradient tool setting the range from 254 to 255 using 16 bits.

Here's the contrast enhanced two images scanned at 2400 DPI (to see the dots) .

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