Save with 5:6:5 bit depth

[MickH74]

Hi there,

In Affinity Photo I would like to reduce the amount of colors in a picture to 16bit total (e.g. 5:6:5 bits per channel) and cannot find out how to do it.

I see color profiles, which I can apply, but I have no idea which - if any - of these is the right one.

Can someone help?

 

Thanks!

Michael

[DWright]

To change the colour profile of a photo to 16bit from the Document menu click Convert Format / ICC profile and then in the pop up menu and in the Format select RGB/16 from the drop-down list and then click Convert and the photo will now be using 16bit colours

[walt.farrell]

3 hours ago, DWright said:

To change the colour profile of a photo to 16bit from the Document menu click Convert Format / ICC profile and then in the pop up menu and in the Format select RGB/16 from the drop-down list and then click Convert and the photo will now be using 16bit colours

Doesn't RGB-16 give 48 bits total (16 per channel) rather than 16 bits total that Michael wants? Though I must admit I'm confused by "16bit total" and "5:6:5 bits per channel" in the post.

I was thinking that Michael might want to investigate Exporting as a palettized PNG file using the More dialog while doing the PNG export, but I'm not sure that's it, either.

[lacerto]

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[MickH74]

Thanks for your answers!

To clarify: yes, I need 16 bits in total and not 16bit per channel. I read somewhere, that the total of 16 bits is distributed on the RGB-Channels as 5 bit for red, 6 bit for blue and 5 bit for green. That´s why I used 5:6:5 equally to 16 bits total. But maybe it is not.

Let me explain the use of the lower bit graphics. Our company is using terminal server with IGEL-clients. They do not support 24 bit graphics and convert them to a 16 bit version automatically. But then soft color changes (like clouds or shadows) become very harsh and ugly.

Therefore, I wanted to convert background images up front to 16 bit.

But maybe that would not help. I can imagine that the picture would just look like the automatically converted one, since there is no color range saved in the picture itself.

Another thing I have to watch is the file size. I would like to stay in the 300 KB range for a 4k-resolution jpeg. Using BMP is 3 MB or more and therefore no option.

Any idea is welcome! :-)

[Pšenda]

1 hour ago, MickH74 said:

I read somewhere, that the total of 16 bits is distributed on the RGB-Channels as 5 bit for red, 6 bit for blue and 5 bit for green.

High color (15/16-bit)

Using two bytes to store each pixel allows 16 bits to be used. Most often these are used for 5 bits of each color plus one unused bit (or used for a mask channel or to switch to indexed color) enabling 32,768 colors, or there can be 5 bits for red, 6 bits for green, and 5 bits for blue, for 65,536 colors with no transparency. These color depths are sometimes used in small devices with a color display, such as mobile telephones, and are sometimes considered sufficient to display photographic images.

https://en.m.wikipedia.org/wiki/Color_depth

[lacerto]

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[MickH74]

Thanks. What @Pšenda wrote is exactly what I mean.

The file size is a minor problem. I already got below 300 KB with 24-bit and 4K resolution and the image is still quite good. I assume th file gets smaller when reducing the bit depth.

But I agree, it is very difficult to find a converter. High-Color is just too old...