French Stamp : #6 Or #6A ?

Hello everyone !
I have this stamp, and when I compared the two different shades of blue, I concluded that that's a #6a from 1850. Am I right ?

Thanks, CS

It is amazing after dozens of threads about color, folks keep asking for the impossible on an internet linked computer.

Oh sorry I understand I thought that maybe it was still possible to remark for this one

There are five shades of this stamp - picking one from a web image is unwise.

You have to scan it adjacent to a known color in order to compare using scans. By itself the scanner or camera will have adjusted the color for you. In your case the paper looks like a toned white paper or perhaps the yellowish. Scan it beside others...

Shades of the same color on the computer are hard to discern even when side by side. All you really answer is the colors are different but not what the actual color is.

That said, there are a small few stamps for which comparing colors can be done on the computer. This five cent stamp shown below was issued in a nice pretty blue color and the stamp paid 5 cents in postage or fees. It was blue to comply with the UPU general requirement that first unit international letter mail stamps were to be blue. It does not matter exactly what shade of blue shows on the computer.




Now sometimes someone finds the same stamp in a color other than blue. Clearly it is not a different shade of blue unless my scanner was played with or is having a bad day. This is the other shade of the exact same stamp from the same die and transfer roll. Can you tell this stamp's shade has departed from blue?



Because of the different color, this stamp could only pay 2 cents in postage or fees.

Why is that? It is the same stamp.

My next post below will explain.

I showed you the color differences that can actual be seen clearly on the basic computer screen color differences for the same stamp. Such color differences confuse some folks. If a red stamp can be blue and a blue stamp can be red, why can't my stamp which is a funny color be real even if it was a chemical color changeling.




The design of the blue stamp was pressed into the wrong plate and showed up in three places in a printing sheet of other wise 2 cent stamps which are red.

NOTE: The color terms here and in the post above are general Blue and Red, not the specific color terms of art used in philately.

Yeah I see ! Thanks for the advices ! What should I exactly do to make the color easier to be seen exactly like it is ?

Forget about colour. There are 100 other things that will take you 20 years to learn about stamps.

Compare in person in indirect sunlight. As to the computer, nothing much can be done at this time.

Even what I showed had a "Black" background which while black was inconsistent from image to image. and software interpretation.The two red five cents stamp don't even look the same because of lighting/

Now if you want to really make you head hurt, see this thread: https://goscf.com/t/88600

Based solely on the scan (and a little bit of experience) I'd say yes you are correct

Thanks Bobby de la rue and thanks for other advices everyone !

The light you are using would colour the paper yellowish in any picture and change the blue shade. Identifying it as a 6a is pure speculation with such lighting.

Hmm I understand, I should change the lightning

You should not check for colours under a lamp that emits coloured light. Nor should you do it with ambient lighting. Scans tend to be much better than photographs.

But the basic message remains, you cannot tell a 'shade' from a picture on the internet.

Captain Stamp has the stamp, and is best positioned to determine the tint of the paper. Of course it may be a 6b but we won't know from a scan as NSK has correctly pointed out.

Anyway, here's my two 25c for comparison.