Identifying stamp color

This is interesting. I hope I get some time to test later.

Vingt Cent

Agreed stainlessb - quality of the scanner was my first thought to, at least if comparing stamps with 'external' data. However if only comparing your own stamps, scanned with the same scanner, at least it can help to divide between them of which has more red or less blue etc.

tobben63 - Yes, I think the results confirmed what I was thinking in advance. The stamp I initially had down as 'Dark brown' (COB #1c) I also considered potentially 'Red brown' (COB #1h), however I ruled it away due to scarcity given for this shade in COB catalog. But, the analysis do actually indicate it has quite a lot of reddish in it, or purplish. So maybe the mahogany brown (COB 1f)? Need to see receive the stamps and see them with my own eyes. Maybe the seller even manipulated the images to show more shades than they really are, I have experienced that with some sellers before unfortunately.

By the way - tobben63 - you must crop away the black background surrounding the images before running the color test, else the black background will affect and skew the results 

Yes I thought about that when I posted the result. Will have to do a better try next time

It would be helpful if there was an HTML code equivalent to the colors (which one primary blue, red, yellow?   middle tones...)

fod8o8   really doesn't mean much to me (old school....sigh)

Great @kasvik
Relly look forward to what you can present here. I have put on hold all the shading of my early stamps from Belgium until I have learned more of "the mystery of color".


Shal we start a new tread for "Identifying stamp color" ? It will be easyer later to find and we might manage to keep this tread on "line"

"Side-by-side eye-balling makes a monkey out of everyone."
Hahaha @kasvik, good observation, just like how I feel at times!!

This subject of establishing shades is fascinating, great contributions by everyone. Agree with you tobben63, it's a good idea to make a separate thread for this particular subject.
Admins, can anyone of you fine gentlemen move the later posts from this Belgium thread to a separate thread for analysing color shades? Thanks for helping! 😊

Thanks to our great admins for splitting this subject into a new thread as suggested


HTML    - that seems a bit on the scientific side for me 
As already mentioned - the results of this is down to the quality of the scanners anyway, so images of the same stamp from different scanners would easily get different codes. Furthermore the catalog publishers probably did not refer to HTML codes anyway. The color-names used in the catalogs I believe remain as they were once defined decades ago -  or even a century before HTML came around, and the color names are far from consistent between catalogs or even within the same catalog. So I think I'll pass the HTML part of it for now, as it seems difficult to achieve any consistency, which is sad.

Obviously HTML came around to achieve consistency and not vice verca. Maybe some day catalog publishers will reveal their 'secrets' by referring to HTML for each of the listed shades? And even better if all catalog publishers could agree on the names for each of these HTML's, like in the link from stainlessb . That would be grand! Unfortunately I don't think the publishers will ever agree.... This is where the online stamp catalogs could take advantage - by listing HTML for each shade, and allowing experts to contribute and add the correct HTML for each shade variety.

For now I will rely on own judgement and by comparing with images of 'reference collection's made by more knowledgeable collectors. Still think the 'Color extractor' is a great tool due to its ability to isolate the colors of a stamp into different fractions - and represent each of those fractions with matching colored boxes and percentages. I find those colored boxes very useful to help evaluating which shade is which.

I just tried scanning a color from my SG Stamp Colour Key and using the color extractor. I selected Ultramarine as this is a somewhat common color.... I wanted to see which HTML code it would apply 

Apparently the color extractor is unable to determine only a single/solid color as the results came back as 000000 (Black)

I retried with a portion of the center hole in the color "chip", with  black as the background as well as some white from the cut edge of the paper

...same result

this leaves me somewhat suspect as to how useful the extractor actually is. Interesting, yes, but useful?

but- curious as I am- I scanned two stamps from a vertical pair -  the amount of obliteration and some variation in the engraved image (different plate position?)
this is the upper stamp

this is the one below it


To my eye, the lower stamp appears slightly lighter... perhaps an optical illusion owing to slightly less obliteration (?)     I tried the extractor and maybe the extractor isn't working this morning as the results for these..... also 000000 (black)

Perhaps the "eye" and sample comparisons of others is the better way to approach this.  In the case of the medalions, each stamp shade is printed with one color of ink, on paper which is more ore less uniform in color, and then a one color (black) ink is used for the obliteration.  

I hadn't notice before just how much difference from one stamp to the next... here's the vertical pair as a single scan

and here's a horizontal pair

Ok, today I have been eye-balling and yes, I feel like a monkey!

I thought when buying a colour guide everything should be easy! But this is a specialist job (you are not a car mechanic because you own a toolbox). Noting wrong with the colour guide, it helps but it is far far from easy. But I enjoy it. Learn a lot, and today's mistakes can be corrected later, it's my collection.

This is why I love the definitives who are reprinted and colour are manually blended, paper changed and perforation are changed. Access to lot of stamps and you can start eye-balling. 

This is the conclusion of today's work. 

Click on image to get a better view. 

Haha, I recognize the eye-balling over this page tobben63 . I was struggling myself, in particular with all the nuances of the 1,75 Fr and the 20 Fr-perf 14. Seems you've found some prominent shades of blue!  (Note - Years of issue was included for each shade to assist in identification!)

   

Have to check this

You where right Jon blaamand , it was the 1968 with phosphorescent paper, witch I had ignored on the other side. But I had one without phosphor to and moved the first one to the right spot. And I also find a 10Frank with phosphorescent paper.

So, the circled area is now filled up with the right stamps. 

Thanks for checking.