Watermark Detectors

edited January 11 in Questions 1 LikesVote Down
Hi everyone,

I'm really thinking about making a big purchase and I need more information so I'm reaching out to ask all of your opinions about the "Sherlock Watermark Detector" from Lighthouse. I got a notice from Subway Stamps that this is a new item they are selling and it really looks interesting. I have the fluid Clarity, but on some stamps I'm still having trouble seeing the watermarks. Not only that but the fluid dries rapidly and I'm not able to adjust my eyes fast enough to recognize the WM. Even when I give the stamp more fluid.

Can someone talk me out of this purchase, or maybe help me over the edge and recommend it?

Thanks for your thoughts,

Thought maybe I'd also include the description:

With the SHERLOCK watermark detector, reveal every detail of your stamps, whether it is watermarks or paper irregularities, quality defects, or repairs.
Easy to use: Insert stamp, turn on the light, and you can already see the secrets of your stamps in every detail – no chemicals needed, therefore no danger for your stamps.
The special feature of this watermark detector is the different light colors (white, red, green, and blue), which can be chosen to light up the stamp. The brightness of the powerful LEDs can be infinitely adjusted. Reveal hard-to-find watermarks with this wide spectrum of color and brightness.
The SHERLOCK watermark detector: A compact unit with the technical sophistication of a professional device. Suitable for stamps up to 2 x 1 ¾" (50 x 45 mm) in size. Battery powered (4 x 1.5 V AA batteries, not included).
Reinforced plastic housing. Made in England.
Overall size: 3 5/8 x 5 1/8 x 5 7/8" (93 x 130 x 150 mm).


  • 19 Comments sorted by Votes Date Added
  • If you do decide on the purchase I would love to know your opinion of this device.
  • Hi, Luree --

    I got that email as well and wondered about that new device.

    Not to sound too cynical, but I have tried some (electronic) devices for watermarks, perforations, etc., and they typically seem to over-promise and under-deliver. That said, I have no experience with this particular device.

    I have found a discussion about the Sherlock on another stamp discussion board, prompted by that same Subway email. But if I recall correctly, this board does not like links to other boards, so I'll send you that link by PM.

    Also, while I do use Clarity in certain cases (including colored cancels), I usually use lighter fluid. It does not evaporate quite as quickly as Clarity, and, because it's far less expensive, I'm less likely to be stingy with it. (If anything, I've found that I've identified the watermark and am waiting for the lighter fluid to evaporate.) As always, the precautions to use it in a well-ventilated area are a good idea. (I've gotten a little dizzy when I didn't. Not recommended - lol.)

    -- Dave


  • Looks like we all got the Subway email.

    I agree with Dave - over-priced with no significant results. I've used Ronsinol lighter fluid and a black tray for years. It outperforms Clarity.

    I, too, would be interested in opinions if someone does purchase this item.
  • Having a great watermark detector may not be enough if one deals with rare stamps! The rarest Canadian stamp is the 2c laid paper Large Queen used in 1870 and apparently all used in Hamilton, Ontario. One of the most recent, said to be genuine, was found in a sales circuit book for a cost of a few dollars by some lucky collector. Thus far 3 found with a current catalogue for USC Fine of CDN. $350.000. Paper was an important factor to determine if the latest find was genuine including checking the thickness of the paper. The 3c Laid Paper, not as valuable as the 2c, has been found rebacked with a thin laid paper. Soaking several times may separate the papers removing the added laid lines. One of the faked laid lines I recall from years ago when put in watermark fluid the laid lines would gradually fade out. Keep you eyes open there are many opportunities to make a buck (or lose a buck in philately).
  • Hi Luree,

    Internally it looks like it uses the same pressure plate technology that the Sign-O-Scope does - thick lens presses stamp on platen. The colored lights are nice but you use colored cellophane with the Sign-O-Scope for the same effect.

    I think I paid $285 for my Sign=O=Scope back in the 80's. Does it work - sorta. It has the same limitations with certain colors that watermark fluid has - yellows are difficult or impossible, especially W-F issues.

    I use lighter fluid as well - haven't damaged anything yet in 30 years of trying.

    Every once in awhile it makes sense to try to find a watermark that fluid doesn't work on but I have only had success a couple of times. What DOES work sometimes is scanning the back of the stamp and playing with everything -- brightness, contrast, color, saturation, size, orientation, etc. You can filter out heavy cancels, colors, etc pretty easy. Give it a try before popping for $300. In looking at catalog values of the more common W-F issues you can just sell the unidentified ones as the cheapest values all day for a lot less than $300.

    I do agree with John regarding finding hi-cat rarities and when I was turning over boxes of stamps on a weekly basis at shows it was most important to be able to recognize "possibles" - they can be set aside for opinions later. I remember getting excited at finding a set of stamps that cataloged $800 in a junk box. The second printing cataloged $20 or $30. The next show I wandered over to another dealers table and said "Hey, Bill....." he glanced over and said "2nd printing" without skipping a beat. He pulled out a set of the first printing and I have to admit even when he pointed out the difference it was hard for me to tell. But he knew from a quick glance as I approaching his table. Dealers are usually happy to share their knowledge.
  • Luree - When I grew up in London (so we're going back to the late 1960's, early 1970's) I bought myself an electronic watermark detector called the 'Philatector' which by your description works similarly to the Sherlock. Both are made in England so perhaps the Sherlock is a modern-day version.. Like the Sherlock, the Philatector is also battery powered. (when we moved back to the States, I needed to modify it a little to take a US 9v battery). It has an integral wheel of colour filters with additional external filters, and uses a basic flashlight bulb as its light source (here, the Sherlock's led's may be of some advantage...brighter with less heat). I still use my Philatector today. With easy watermarks, it works really well, but it can be iffy on the really tough ones (which are also tough to see in fluid). I can't imagine that the Sherlock is that much better, but have no experience. I dunno how much the Sherlock costs, but you may want to consider looking for a Philatector on that other site. They show up every once in a while and are pretty inexpensive, making for an acceptable entry-level electronic detector.
  • edited January 12 0 LikesVote Down
    The Sherlock has a list price of $325.00 USD.

    I had a Philatector in the 1970s as well. I didn't like it at all. I have found that using a bright light or watermark fluid is still the best way to see watermarks (and now so) much cheaper as well.
  • I agree with Michael. I have a Philatector also. It doesn't work the best with the harder watermarks. I either use Clarity or Ronsonol now.
  • Thank you all for replying. I just don't know which way to go. I really don't like using the lighter fluid. It would mean going outside and let's face it, I'm too lazy! The Clarity just doesn't last very long for me to recognize the WM and decide if I'm really seeing what I'm supposed to be seeing, or wishful thinking.

    I'm going to ponder this a little bit more and then make a decision and let ya'll know which way, stay with Clarity or take a deep breath and spring for an electronic device.

    Anybody else want to chime it, all thoughts are welcome.

    Have a super weekend,
  • edited January 12 0 LikesVote Down

    I don't know if this is true for others or not, but I do use the lighter fluid indoors. However, I make sure to have a door or window open -- usually both. (I have on occasion pointed a fan out the door for increased ventilation if I'm doing a lot of watermarking.)

    Because of our weather in Southern California, having doors and windows open is usually not hard to do. (I imagine it would be the same for you.)


  • I don't know about the evaporation rate of Clarity. I use Prinz watermark fluid, and it lasts long enough for me for most stamps.
  • I use a bookmark with a (flat) LED light on one end ( like this: https://www.amazon.com/Bendy-Booklight-Bookmark/dp/B00H1XU5DQ ) that I place the stamp on. It works for me and well worth trying before throwing away a lot of money.
  • edited January 13 0 LikesVote Down
    Interesting debate, I wish the machines were better on the hard to see watermarks. Australian Kangaroos have been kicking my butt. Recently won a small battle
    with Leeward Islands. Unfortunately waterfluid bottles never last as long as you would like.

  • Andrew, the LED bookmark shows roo watermarks just fine. Here's some photos. (My phone photo skills are lousy. Results are much better than this, showing too much glare here).
  • That's interesting, Rod. It made me think of whether anyone has tried to use the screen on their phones in a similar fashion? I think the screen can be set to shine brightly. I don't have a smart phone, so I don't know. I'll give it a try on the small screen of my old flip phone.
  • edited January 13 0 LikesVote Down
    I have tried getting a bright white only smartphone screen too, but couldn't find a way (I gave up quickly as I HATE those phones). Need a phone aficionado to tell us how. :)

    The LED option also works somewhat with a LED torch (but usually too bright) which most will have to try out. I just like the bookmark as it's small and flat and always on hand.
  • You can go to the app store for your phone and search for White Screen. There are many apps with those words in the name. Just download the one with the highest rating.
  • With my flip phone, I went to the text messages application. The create message screen is white. I put a stamp on the screen. The watermark shown through. It was similar to holding a stamp up to a light. I did this with a few stamps. Not much to write about, but if at a show, this would be a good way to check out a stamp that has a watermark that isn't too difficult to see.
  • What wonderful ideas.

    So all this got me to thinking ... when I was into photography I was buying different colored filters to change the pictures and shoot really cool pictures. Dug them out and found a brown (sepia) and a yellow full filter. I put the stamp on the sepia then the stamp and the yellow on top then an LED light to shine through all. Nicely saw the watermarks. I also dug out the lighter fluid and got another WMK from a different stamp that had a little bit of paper on the back.

    I'm going to try all methods and one will stay a constant for me.
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