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thomaso

JPG export – Color Space selection

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Is there a way to select the color space RGB for an export of a CMYK document as JPG?

I wonder if I just don't see the setting – cause for PDF and TIFF I see free choice, and even for GIF a little. – But none for JPG.


macOS 10.12.6,  Macbook Pro 15" + Eizo 24"

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More... dialog, Pixel Format:

pixelformat.png.f03cbe7b0ad6b45d40a1f78d54618fda.png


-- Walt

Windows 10 Home, version 1903 (18362.356), 16GB memory, Intel Core i7-6700K @ 4.00Gz, GeForce GTX 970
Affinity Photo 1.7.3.481 and 1.8.0.486 Beta   / Affinity Designer 1.7.3.481 and 1.8.0.486 Beta  / Affinity Publisher 1.7.3.481 and 1.7.3.475 Beta

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40 minutes ago, walt.farrell said:

Pixel Format:

Wow, Thank you, Walt! – Again you guide me to an option which sounds quite different to me but does what I want. :)

– Any idea why here "Color Space" is called "format"? And why "Pixel", since JPG is pixel only? I thought that would refer to output dimensions in a way and therefore I did not try it. Also this option's position seems odd: not next to "ICC profile" but above the "Resampler" selection.


macOS 10.12.6,  Macbook Pro 15" + Eizo 24"

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25 minutes ago, thomaso said:

Any idea why here "Color Space" is called "format"?

Good question. The nomenclature here is obscure / confusing. 

I would suggest a label that is consistent across all export dialog boxes and across all Affinity applications – something like "Export Color Space".

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9 hours ago, thomaso said:

And why "Pixel",

I think it's Pixel Format because it's letting you specify whether the pixels are 8- or 16-bit. And because you're choosing whether they're RGB or CMYK or Grayscale format. But yes, some consistency with other parts of the UI would be nice...


-- Walt

Windows 10 Home, version 1903 (18362.356), 16GB memory, Intel Core i7-6700K @ 4.00Gz, GeForce GTX 970
Affinity Photo 1.7.3.481 and 1.8.0.486 Beta   / Affinity Designer 1.7.3.481 and 1.8.0.486 Beta  / Affinity Publisher 1.7.3.481 and 1.7.3.475 Beta

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I am less confused by the inconsistency but more by the words "pixel" + "format". The term "format" here stands for "space" / "range" / "area" referring to "Color". Is "color format" in English a synonym for "color space" or "color model" ? (sorry, it might sound stupid, I think my concern is caused by my native non-English tongue "format".)

    > Pixel Format because (...) you specify whether the pixels are 8- or 16-bit.

So the label also could be "Vector Format" because the vector item's colors get converted to the chosen bit rate, too? Or "Pixel Space"? Or simply "Your Format" because it was your, the user's, choice?

I just can't see any additional or useful information given with the term "Pixel" in this menu's label for "Color Space" (or "Color Format") selection.


macOS 10.12.6,  Macbook Pro 15" + Eizo 24"

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On 10/12/2019 at 8:46 PM, thomaso said:

Any idea why here "Color Space" is called "format"?

Technically, a color model is an abstract method of describing color, usually one related in some way to human color perception. A color space defines how the colors are ordered or represented in a color model, like as tuples or as named & numbered values like in the Pantone proprietary color spaces. But a color space does not by itself define the quantization (bit depth) of the color space.

So technically, the popup does not just offer a choice of a color space but also the quantization of that space. Thus it is offering a choice of color format. Of course, since JPEGs always use 8 bit quantization, there are no 16 bit choices for that format but there are for other export formats.

Also, note that the "Pixel format" popup only appears for raster image (pixel) export formats like JPEG, PNG, TGA, or TIFF.

So at least technically, this not a "color space" chooser. Instead it is what it says it is, that being a "pixel format" chooser.


Affinity Photo 1.7.3, Affinity Designer 1.7.3, Affinity Publisher 1.7.3; macOS High Sierra 10.13.6 iMac (27-inch, Late 2012); 2.9GHz i5 CPU; NVIDIA GeForce GTX 660M; 8GB RAM
Affinity Photo 1.7.3.155 & Affinity Designer 1.7.3.1 for iPad; 6th Generation iPad 32 GB; Apple Pencil; iPadOS 13.1.2

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On 10/14/2019 at 12:41 PM, R C-R said:

Technically, a color model is an abstract method of describing color, usually one related in some way to human color perception. A color space defines how the colors are ordered or represented in a color model, like as tuples or as named & numbered values like in the Pantone proprietary color spaces. But a color space does not by itself define the quantization (bit depth) of the color space.

Thank you, R C-R!  I haven't been aware about the fact that differences of for instance "Color space 1-bit" and "Color space 24-bit" are technically spoken no property of color space but have a separate, superordinate term "Pixel format".

While a web-search for "Pixel format" mainly shows results related to dimensions + ratio, the following info makes it more clear by describing format as "layout" and mentioning "channel" and examples rather related to video than to RGB screen appearance or even CMYK or Pantone print (which I am simply used to verbally distinguish by their channels rather than their actual bit depths):

694460202_PixelFormat-Whatis.jpg.7ee0437b6c317755157c6b5389fd36bc.jpg


macOS 10.12.6,  Macbook Pro 15" + Eizo 24"

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21 minutes ago, thomaso said:

 I haven't been aware about the fact that differences of for instance "Color space 1-bit" and "Color space 24-bit" are technically spoken no property of color space but have a separate, superordinate term "Pixel format".

It doesn't help that "color space" is often used as a sort of catch-all phrase that variously can mean a color model, any of several abstract mathematical spaces, a color format (color space + bit depth), a particular indexed or discrete color scheme, sometimes even a specific ICC profile, or almost anything else that refers to digitized color representations.

It also doesn't help that even complex abstract mathematical models cannot accurately model how we perceive colors, or for that matter that human vision is a dynamic process cameras cannot duplicate.


Affinity Photo 1.7.3, Affinity Designer 1.7.3, Affinity Publisher 1.7.3; macOS High Sierra 10.13.6 iMac (27-inch, Late 2012); 2.9GHz i5 CPU; NVIDIA GeForce GTX 660M; 8GB RAM
Affinity Photo 1.7.3.155 & Affinity Designer 1.7.3.1 for iPad; 6th Generation iPad 32 GB; Apple Pencil; iPadOS 13.1.2

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> It doesn't help

For everyday use, it usually does not matter that "reality is not really real". Such simplistic models help in communicating about events like colors and might save lives when we automatically identify the wavelengths of a scream or red and green light, without knowing at all about the physics, chemistry, and emotions that create such impressions.

Thank you for linking to this rich illustrated (simplified;) info source  https://www.cambridgeincolour.com


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