On 9/14/2013 11:56 PM, Victor Manta wrote:
"Terry Reedy" wrote in message
...
On 9/14/2013 2:36 PM, Victor Manta wrote:
How would you describe the condition of this S/S?

Perhaps lightly wrinkled.

How would you grade its quality?

I understand 'grade' to mostly refer to centering, of single stamps.
That is not so much an issue for SS, but this one is well centered.


http://www.artonstamps.org/topicals/...sheet-face.pdf
http://www.artonstamps.org/topicals/...sheet-back.pdf

Would someone also explain what causes such flows.

Do you mean real flaws? (if so, which? I am not sure I see any other
than some minor curl and wrinkle) or apparent flaws from the scan
shadow? For the latter, a scanner has to have the light offset from
the sensors, (and the sensors shielded from the light). The scanner
used here seems to have sensors pointing straight up with light
hitting as a noticeable angle. Did you have the lid down on the
scanner, to flatten the sheet?

Terry


Note about the scans:
The gray band on the top of the image of the back is a shadow that
doesn't really appear on the S/S. The same applies to the gray shadows
that appear on the indentations (saliencies?) on both faces and
certainly highlight (by amplifying) the flaws.

Thank you, Terry! Yes, the lid of the scanner was down and therefore the
sheet was flattened.

Here is what I found a few hours ago:

"Instances where the gum can affect the numerical grade or be mentioned
in the opinion mostly emanate from the actual process of the gum drying
after being laid down at the time of application. As the gum dries after
this application, several things may occur, most of which are considered
minor faults:

1.Gum Bends – light bends in the gum but no crease in the paper.
2.Gum Creases – bends in the gum that actually cause a crease or pucker
in the paper in the affected area."

http://www.stampauthentication.com/Grading.html

Considering this quote, and the fact that I see many bends on the face
of the S/S too, I'm inclined to believe that:

- These faults in the gum, eventually leading to creases in the paper
itself, affect the grading

- The important number of these flaws, many of them visible with the
naked eye on both faces, should drive the grading quite low

- Even if the scanning process brings some visual distortions (or
enhancements) of the flaws, its result point us correctly to the flaws
themselves and make them better visible on the scans.

I'll be glad if somebody proves me wrong, because I'm in possession of
this S/S :-)

As I understand it from the quotation above, the flaws come from the
improper drying of the gum during the fabrication, which means that this
sheet looked always like this. I wonder if maybe it has been improperly
stored starting by 1961, like going through humid - dry, cold - hot cycles.

It is possible that you would be better off soaking off the gum ;-)