Jack, Glad to hear it's helping! Is wet scanning with Clarity any better or worse than with Ronsonol? Maybe you could post scans of the same stamp, each with a different fluid, but don't tell us which is which? That would allow all of us to make our own opinion.
Dave, I agree that we should see at least some darker uninked areas. However, I don't know all of the characteristics of watermarks nor expertisation detection methods.
I use fluids myself, but have a left-over 'toy' from my youth that I bought in London back in the late 1960's or so that works remarkably well. Its called the Philatector which uses an integral wheel of coloured filters (as well as some additional ones that can be slid in) with a battery powered light source. No fuss, no mess, but sometimes I have to kill the room lights to see some of the more difficult ones. These can occasionally be found on eBay and are nowhere near as expensive as the Scope.
The one on eBay has been retrofitted to fit current battery types, which I had to do myself. It used to take a 5.4 volt battery that was flat and around 3 x 2 inches in size with rounded edges, and both terminals on the top (as flat metal blades). I refitted mine to take a single 9-volt battery which was a piece of cake to do.
Tried the wet scan technique for the first time (using Clarity...haven't picked up any Ronsonol, yet). It definitely works. And Clarity did not evaporate too fast for the scan. Do to the concerns mentioned about liquid damaging the scanner, I did do it in the middle of the scanner glass (farthest from any cracks).
Very excellent and informative posts in this thread. Sounds like Ronsonol does a better job than Clarity and I am not concerned about flammability or toxicity. Common sense when using Ronsonol must prevail.
As far as the T1, I have only used it on MNH Commonwealth and have successfully ID'd watermarks not visible with Ronsonol. The spacers create a substantial advantage for thick-paper Commonwealth. As far as potential damage, I gradually increase the pressure over a few seconds time until I see the watermark and then back off, never to put that stamp back into the device again. I do agree that all Signoscopes are too small for multiples so another method must be used.
I cannot speak to the T1's value for US as most of you have forgotten more about US philately then I will ever know.
I got Ronsonol for the first time last week and have tested it a little. It seems to make most watermarks "pop" out better than Clarity. However, I was still having a lot of difficulty with W/Ms on yellow or orange paper, so I'm did a little test on the same stamp. I think the Clarity worked better. There seems to be part of a single line mark under the 4th top perf from right that doesn't correlate to ink on the other side. It's easier to see with Clarity (first image). So for orange/yellow, Clarity works better. For everything else, Ronsonol seems to work better. Anyone else had this experience?
First off, I do believe that Clarity performs more effectively than Ronsonal on orange/yellow stamps. Some say also olive green. What has not been discussed on this thread is the usage of filters. For example, using Windows Photo Gallery (and others) after wet scanning the stamp. Doing so provides different effects. You can tint the stamp blue, grey. green, etc Each time you'll get a different effect and the watermark can be more easily seen.
I am not sure what we see here in the top scan. There is something there. And the Clarity is clearly better. At first I thought it was part of an "S". But now I think I'm seeing the bottom half of a "U". I'm probably wrong because every time (almost), I always see a "U"! Comment are most welcome here.
lukusw, Your two wet scans don't have enough detail. It looks like the image optimizer didn't work well. Their "Levels" are out of whack. Scanning at a lower resolution like 600 dpi would help. Also, I can help you compress them below the image maximum size limit. Reply to the email I sent you if you like.