Identifying Stamp Colors

By Don Denman
Digital Imaging for Stamp Collectors
Stamp Image Color Extractor

Stamp colors are probably the most confounding areas of collecting. And it is very tempting to use technology to help us find answers to our color questions but there are many issues and short-comings surrounding accurate color representations when using technical solutions.

Before we begin discussing the technology we should mention some of the ‘human’ color challenges. What one person may see as red another person may see as scarlet. This can be explained by the fact that we all have a unique number of cones and rods in our eyes. Additionally research has proven that men and women see colors differently. Another important factor is that how we see colors is greatly impacted by the ambient light conditions we view it in. Viewing a stamp under ‘office lighting’ and then viewing the same stamp under natural sunlight will reveal just how much ambient light conditions influence how we perceive stamp colors. It is not intellectually honest to have a stamp color discussion without defining the ambient light conditions.

And no discussion about colors could be complete without mention of inks and color fastness. A stamp’s color is ephemeral, the chemistry of inks start changing as soon as it is printed. How well a stamp is able to retain its original color is largely dependent upon the environmental conditions is has seen since it was printed. Even if a stamp is kept in a darkened drawer for its entire life certain chemical changes can take place which can change the color of a stamp. Obvious examples are the oranges inks used on many stamp at the turn of the century.

Another thing to keep in mind is that we rarely know what a stamp has been through during its lifetime. Environmental conditions, light exposure, and even soaking can all have an impact of the color of a stamp. If a stamp was applied to an envelope, mailed, and the envelope was left sitting on the dashboard of a car or on a desk near a sunny window; it will most assuredly show a color change. It can safely be said that identifying a used stamp color is much more challenging than a mint stamp.

Before moving on to the technical aspects of identifying colors we should mention color ‘names’. It is important to understand that many philatelic publishers have, throughout the ages, never standardized on stamp color names. (A few attempts have been published but none have been universally adopted.) The lack of any universally accepted color nomenclature means that what one catalog publisher calls ‘violet’ another might call ‘lavender’.

Now that we have outlined some of the human color challenges we can move on to understanding how technology impacts our perception of stamp colors. Most online stamp images come from one or two sources; either a digital camera or a scanner. The device uses software to generate the image; how accurately the software replicates the true colors is totally dependant upon this code. The software code’s quality (and accuracy) can vary from manufacturer to manufacturer. Another variable that get introduced is how the image file is saved. Many of the image file formats ‘compress’ the image; this represents another opportunity for software to modify the original colored image. Making matters even worse to the likelihood that users may apply various ‘filters’ or other post processing actions which also modify the original colored image.

And the last challenge is how the image is displayed and appears on the device we are using to view. No two displays, even from the same manufacturer, will be exactly the same. And certainly no two computers, complete with various operating systems, video drivers or applications will display a stamp image the same way. No matter how perfectly a stamp image is generated and saved the outputted image is still totally dependent upon on the display device(s).

By this time you may be wondering why you should even bother trying to identify a stamp’s color. Frankly a good argument can be made that the only valid approach to identifying stamp colors is to assemble a large reference collection of a stamp issue, defining and standardizing the ambient environmental lighting, and developing an good eye for the colors. Hopefully one day technology will help us resolve these challenges by doing a full chemical analysis on the stamp ink; providing definitive identification of a stamp’s color.