Centering Questions/ Short Perfs

I was wondering at what point a short perf detracts from a grade of a stamp.

please take a look at stamps below-- I recently picked these out of a large collection. they are from left to right (Scott 418, 465,468, 663) I think

they aren't tremendously valuable but very attractive. the best centered one (to my eye!) is the 465 (second stamp from left). However, it has two shortish perfs at top.

663 Kansas overprint has a shortish perf at top as well. (mint vlh)

Any comments on the effect of the perfs on a grade! Any thoughts if these guys would hit 95+ grades from PSE?

my opinion: no detraction at all for these, but I have never figured out how to tell 90 from 95 from 100 grades.

Agree that the 4c (465) has the best centering, and although there are a couple short-ish perforations at top, I think this still would easily be at least a 95 if a completely sound condition stamp.

The others aren't too bad either, but may be not quite 95 material.

Don't know about a numerical grade but for me personally I'd purchase stamps of that quality any day. I don't see a decrease in value either.

I guess my question is what is definition of "nibbed" perf, "shorter" perf, short" perf, "pulled" perf, etc?

I thought I read a short perf affects grade if it is less than 50 percent of normal size perf? What size defines normal perf or is it defined by 50 % of surrounding acceptable peforations?

Or perhaps this is all nonsense unscientific subjective exercise. Guy grading your stamps may be having a great day or miserable because wife just slept with the plumber.

On 4c stamp above there are two shorter perfs at top but relative to other perfs at top, they don't look so bad and may not affect grade. However relative to left side perfs, they are shorter and perhaps would bring down a grade???

comments on short perf at bottom of this one.

this mint stamp looks awesome to me -- the impression is so sharp! trace of hinge on back.

only thing I see is "nib" or short perf on bottom about 8th perf from left. Would that get called out on a certificate? Would it detract from grade? Do any of sides look like perf added?

Download the PDF file and read through it. It does discuss short perfs. This may answer your question.

http://gradingmatters.com/all-about-grading.html

The PSE Guide to Grading and Expertizing United States Stamps consider a "short or nibbed perf" as a "minor fault". If I considered the centering of this stamp to be XF-S, with no faults it would have an initial score of 95. With a single "minor fault" the score would be reduced to 80 which would be a stamp of VF condition.


-IBFS

I think this 50c Columbian stamp, faultless, with this centering would grade at best 90. But with short perf it would go down to 75? That is my concern. Not worth $$$ to have graded. Will enjoy it as is!

I believe multiple nibbed or short perfs. is considered a major fault.