Scott #492 Lake? Likely Not.

Scott does not list 492 in Lake variety, and it is likely some sort of color changeling, but it sure looks like Lake, isn't it? The stamp on the right is a regular #492 and the one on the left is the darkest and dirtiest copy of carmine I was able to find.

And with 219D Lake and 220 Carmine on the left.

To be honest, I wouldn't spend much time on shades of used stamps of unknown handling and storage conditions unless they were highly unusual. What you show seems well within the normal variance considering both wartime production and then production/use into the eary 1920s. Just my 2 cents!

I am of the opinion that your stamp I'd not a Lake color. Ink on paper can change in shades due to many factors. One is the paper it self that it is printed on. The envelope it may be attaches to can also chang the color. The adhesive used on the back and any adhesive used after to mount the item. I took a quick look on the scans and used my panatone color chart. It just appears to be a dark carmine.

I agree with John , to make sure of what color a stamp is a unused copy is the best. The used copy can he exposed to many factors that may change its color after being produce.

Even if used, putting a stamp under UV will usually bring up the original shade. UV shows a range of things that the naked eye cannot see.

Also "Lake Ink" must include certain composition in the ink itself to be considered "Lake Ink" otherwise no matter what the stamp looks like, it is not a lake. Some colors are now only considered as certain with testing beyond the "opinion" of a naked eye. Certain brown a well as lake falls into that category, a category which includes machines which the normal collector will never own.

To follow up on parcelpostguy, I posted on another post but no answer came up.
I remember a while back someone was using an app that will scan your stamp and provide analysis of the color content in a chart form and they were using this to compare to the chart of a authenticated stamp. Not sure if this worked or not. I think if it did, they could make the charts available of the authenticated stamps to use for comparison at home. Anybody remember or know of this?

I do not think a smart phone taking a color image can do either a X- ray fluorescence spectroscopy (XRF) nor ATR FT-IR spectroscopy to establish the vibrational groups and associated components of ink. Please correct me if I am wrong.

The problem I inferred before is that unless the ink on the stamp in question has the PROPER components it is NOT the correct color. Correct color is no long accepted just because it looks correct to the human eye, now with science it must have been correctly mixed. So far, lake and certain brown colored USA stamps no longer can be verified by human eye. An yes the expert committees now have access to such science for certain stamps.

Edited, not at all. Thought I made a spelling mistake but I was wrong.

this was done with a scanner and then a graph chart would be created showing an analysis of the color, breaking it down by type and percent of pigment, if I am correct. This app was discussed on this forum. I just can't find it.

No need for the PF or PSE or APEX or PSAG anymore. We have an app!

That sounds like something wert would have claimed. He is no longer with us, but you may have luck searching through his older posts. However, you may not like some of the comments.

I had fun, you can too....

https://goscf.com/t/39790 Smart phone scanning.

https://goscf.com/t/3803&whichpage=1 Issues of determining color now.

https://www.stampcommunity.org/topi...&whichpage=1 Discusses issue using electronics (software) for color determination and replication.

https://goscf.com/t/69549 more detail about source or ambient lighting of the stamp in question.

https://goscf.com/t/79951&whichpage=1 more about ambient lighting.

https://goscf.com/t/37654 especially studebaker51 posts.

Edit: I wish to add that while I mentioned software, the discussions above of touch on hardware which can also have an effect.

Additionally there have been so near scholarly or scholarly level discussion article on scientific determination of color in the USSS' (United States Stamp Society) journal The Specialist.

Thanks parcelpostguy, I looked through them and didn't find the discussion I was talking about. It had an app that compared in a graph chart, recognized standard colors to a portion of your stamp. You were to take a small section of your stamp preferably a solid section and have it scanned for comparison to the standard color carmine. magenta, etc. Then the graph chart of your specimen was compared to the graph chart of the standard color. Any body remember this discussion? You had to pay to use this app.

Yes, I clearly do but doubtful I can find it again. These types of discussions are probably one of the frequent here.

A random scanner cannot do anything for actual chemical analysis.

There is just no proper substitute for direct in-person examination (with the proper tools and know-how to interpret the results) and comparison with other in-hand examples (i.e., a reference collecton.) Scrap the apps.

I agree John, I just was wondering if anything came of it. So my other question is I noticed many of the carmine lakes and lakes with certs have a color range and I assume some even faded or color changed a little. I would assume chemical analysis would still be able to identify but looking with your eye wouldn't?