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Author Topic: angels dancing on the head of a pin?  (Read 1479 times)

rabanito

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angels dancing on the head of a pin?
« on: December 31, 2018, 06:09:49 am »

Speaking of colour spaces, I - an absolute novice in things colour - have some questions

I take "serious" photos in RAW format. Usually I import them with Lightroom which, I am told, uses the ProPhotoRGB colour space.

I do some tinkering as well in Ps and I feel comfortable printing from there.

Now:
For uploading to internet I change from 16 to 8 Bits/Channel and convert to sRGB
Nothing happens visually, as far as I am aware.

Looking at the picture on the Internet, it shows no perceptible changes.
I mean, I don't need to "squeeze" the colours from one space to the other, everything seems to go just right.

I mean:
I prepare a picture. When the picture is ready, I convert the colour space, picture looks the same to me
I send it up the Internet.
I check what is there in my monitor.
It looks exactly the same as what I have, say, in PS

Could there be a problem for gurus, professionals or photographic medicine men, that play no role in my photography because I am not at the level? I can live with that absolutely, just being curious

Thanks for any opinions or teachings  :( :(


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TonyW

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Re: angels dancing on the head of a pin?
« Reply #1 on: December 31, 2018, 06:47:28 am »

It sounds quite possible that most/all of your image data is fitting very closely within sRGB gamut.  Bear in mind the limitations of your monitor gamut e.g. common to be close to sRGB. 

So with these conditions perhaps it is not surprising after all that you are not generally noticing any changes in conversion - limitations of your viewing device. 

IMHO for internet viewing as long as the image looks acceptable to you then that is the best you can provide for others viewing (hoping that they may be looking at a colour managed system!), however, IF you are intending to print then this opens a whole new world of colour gamut potentially exceeding even a wide gamut monitors capabilities with some of the great paper and ink combinations available.

So unless you switch on an out of gamut (OOG) warning for your particular output device (printer?) profile then you will not be aware of any data loss - even then the OOG warning switch on it is not hugely useful as it does not display the degree of OOG.

You could do far worse in furthering your understanding than seeking out some of the excellent tutorials published by Andrew Rodney:
Everything you thought you wanted to know about color gamut:
https://www.youtube.com/watch?v=n0bxSD-Xx-Q

The benefits of wide gamut working spaces on printed output
https://www.youtube.com/watch?v=vLlr7wpAZKs

Just a quick and dirty example.  The attached screenshot is a section from a test image by Bill Atkinson (inset at top whole image).  Brought into PS the left image is the native file 16 bit Prophoto while the right-hand image is a duplicate converted to 8 bit sRGB.  Some areas exhibit no noticeable changes but note what happens in the greens and light cyan patches - appears to be more noticeable using a wide gamut monitor
« Last Edit: December 31, 2018, 07:12:08 am by TonyW »
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rabanito

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Re: angels dancing on the head of a pin?
« Reply #2 on: December 31, 2018, 07:13:51 am »

Thank you Tony I'll watch them.

About printing, I'd prepared a question about that too but decided to leave it for later, so as not to make my explanation still more confusing  :)

But then I'll watch first those tutorials.
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digitaldog

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Re: angels dancing on the head of a pin?
« Reply #3 on: December 31, 2018, 01:27:25 pm »


Now:
For uploading to internet I change from 16 to 8 Bits/Channel and convert to sRGB
Nothing happens visually, as far as I am aware.
Depending on the gamut of the image, it absolutely does change but if you have an sRGB gamut-like display, you can't see any of the colors outside that color gamut that do indeed change.
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David Eichler

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digitaldog

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rabanito

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Re: angels dancing on the head of a pin?
« Reply #6 on: January 02, 2019, 04:33:25 am »

Thank you very much to all for the info.
I'm still digesting the tutorials. Some new ground to me. But I'll make it  ;D

Then I'll come back probably with more questions .

HAPPY NEW YEAR EVERYBODY!
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rabanito

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Re: angels dancing on the head of a pin?
« Reply #7 on: January 04, 2019, 03:53:16 pm »

I can't find the gamut test file mentioned in one of the videos by digitaldog
Any idea?
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digitaldog

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Re: angels dancing on the head of a pin?
« Reply #8 on: January 04, 2019, 03:54:15 pm »

I can't find the gamut test file mentioned in one of the videos by digitaldog
Any idea?


http://www.digitaldog.net/files/Gamut_Test_File_Flat.tif
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rabanito

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Re: angels dancing on the head of a pin?
« Reply #10 on: January 08, 2019, 10:06:17 am »

Depending on the gamut of the image, it absolutely does change but if you have an sRGB gamut-like display, you can't see any of the colors outside that color gamut that do indeed change.

I watched the tutorials and made the prints.
I understand many things better now
Thanks
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