What is Paper White?

We should all know by now that, in RGB terms, BLACK is 0,0,0 and that WHITE is 255,255,255 when expressed in 8 bit colour values.

White can also be 32,768: 32,768: 32,768 when viewed in Photoshop as part of a 16 bit image (though those values are actually 15 bit – yet another story!).

Either way, WHITE is WHITE; or is it?

Take this Arctic Fox image – is anything actually white?  No, far from it! The brightest area of snow is around 238,238,238 which is neutral, but it’s not white but a very light grey.  And we won’t even discuss the “whiteness” of  the fox itself.

The Hen Pheasant above was shot very late on a winters afternoon when the sun was at a very low angle directly behind me – the colour temperature has gone through the roof and everything has taken on a very warm glow which adds to the atmosphere of the image.

We can take the ‘snow at sunset’ idea even further, where the suns rays strike the snow it lights up pink, but the shadows go a deep rich aquamarine blue – what we might call a ‘crossed curves’ scenario, where shadow and lower mid tones are at a low Kelvin temperature, and upper mid tones and highlights are at a much higher Kelvin.

All three of these images might look a little bit ‘too much’ – but try clicking one and viewing it on a darker background without the distractions of the rest of the page – GO ON, TRY IT.

Showing you these three images has a couple of purposes:

Firstly, to show you that “TRUE WHITE” is something you will rarely, if ever, photograph.

Secondly, viewing the same image in a different environment changes the eyes perception of the image.

The secondary purpose is the most important – and it’s all to do with perception; and to put it bluntly, the pack of lies that your eyes and brain lead you to believe is the truth.

Only Mother Nature, wildlife and cameras tell the truth!

So Where’s All This Going Andy, and What’s it got to do with Paper White?

Fair question, but bare with me!

If we go to the camera shop and peruse a selection of printer papers or unprinted paper samplers, our eyes tell us that we are looking at blank sheets of white paper;  but ARE WE?

Each individual sheet of paper appears to be white, but we see very subtle differences which we put down to paper finish.

But if we put a selection of, say Permajet papers together and compare them with ‘true RGB white’ we see the truth of the matter:

Holy Mary Mother of God!!!!!!!!!!!!!!!!

I’ll bet that’s come as a bit of a shocker………

No paper is WHITE; some papers are “warm”; and some are “cool”.

So, if we have a “warmish” toned image it’s going to be a lot easier to “soft proof” that image to a “warm paper” than a cool one – with the result of greater colour reproduction accuracy.

If we were to try and print a “cool” image on to “warm paper” then we’ve got to shift the whole colour balance of the image, in other words warm it up in order for the final print to be perceived as neutral – don’t forget, that sheet of paper looked neutral to you when you stuck it in the printer!

Well, that’s simple enough you might think, but you’d be very, very wrong…

We see colour on a print because the inks allow use to see the paper white through them, but only up to a point.  As colours and tones become darker on our print we see less “paper white” and more reflected colour from the ink surface.

If we shift the colour balance of the entire image – in this case warm it up – we shift the highlight areas so they match the paper white; but we also shift the shadows and darker tones.  These darker areas hide paper white so the colour shift in those areas is most definitely NOT desirable because we want them to be as perceptually neutral as the highlights.

What we need to do in truth is to somehow warm up the higher tonal values while at the same time keep the lowest tonal values the same, and then somehow match all the tones in between the shadows and highlights to the paper.

This is part of the process called SOFT PROOFING – but the job would be a lot easier if we chose to print on a paper whose “paper white” matched the overall image a little more closely.

The Other Kick in the Teeth

Not only are we battling the hue of paper white, or tint if you like, but we also have to take into account the luminance values of the paper – in other words just how “bright” it is.

Those RGB values of paper whites across a spread of Permajet papers – here they are again to save you scrolling back:

not only tell us that there is a tint to the paper due to the three colour channel values being unequal, but they also tell us the brightest value we can “print” – in other words not lay any ink down!

Take Oyster for example; a cracking all-round general printer paper that has a very large colour gamut and is excellent value for money – Permajet deserve a medal for this paper in my opinion because it’s economical and epic!

Its paper white is on average 240 Red, 245 Green ,244 Blue.  If we have any detail in areas of our image that are above 240, 240, 240 then part of that detail will be lost in the print because the red channel minimum density (d-min) tops out at 240; so anything that is 241 red or higher will just not be printed and will show as 240 Red in the paper white.

Again, this is a problem mitigated in the soft proofing process.

But it’s also one of the reasons why the majority of photographers are disappointed with their prints – they look good on screen because they are being displayed with a tonal range of 0 to 255, but printed they just look dull, flat and generally awful.

Just another reason for adopting a Colour Managed Work Flow!

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