Surely this is an excellent technological approach but a) I guess it wasn’t used yet and b) I see no reason for ‘ink on ink’ analysis?

What exactly would be your expectation from such analysis? On Z letters?

QT

Surely this is an excellent technological approach but a) I guess it wasn’t used yet and b) I see no reason for ‘ink on ink’ analysis?

What exactly would be your expectation from such analysis? On Z letters?

QT

I’m beginning to guess nobody has tried this either. I can understand why some
people may not see a reason for this type of deep analysis. Analysis of layers of ink
could reveal different types of inks. These different types of inks which are known
to not be visible could reveal an entirety different message from the writer. Or
maybe there is a different type of ink under or over the primary ink, still visible,
But by digitally removing a layer, a different message could be revealed. Maybe it’s
the same type of ink, and the writer added a 2nd layer of parts of existing layers of
Ink to pass a hidden message. The writer was clearly into hidden messages. Who
knows what this person did.

If this were to actually be done, my exact expectation(s) would be:

1. Verification. Any possible results using these methods are eliminated.
Also that the evidence is not altered or damage in any way during testing.

2. I’m looking for further encrypted/hidden unencrypted messages than may not have even
been detected yet. In order to let the evidence speak for itself, it must be given the
venue to so. If this individual(s) we’re in fact into ciphers/hidden messages, then I would
be very surprised that they didn’t do this. Invisible inks have been widely used in
Intelligence gathering communities around the world for a long time. And lots of people
were, (and still are) very unsuspecting of it.

3. If the writer ( or anybody else) wrote something personal (ie their actual return name
and address on top of anything he sent, (Paper, envelopes, ) on a different piece paper,
envelope, or even the surface of the Inside of the envelope, that is NOT detectable with your
eyes, or through a graphite rubbing of the surface. Then; the density changes to the substrate
caused by the action of applying pressure with a pointed foreign object ( a pen, and I bet this
Is why he used felt tip) then the density changes could very well still be detectable through
CR. Then again, it may not be. Which is mostly my point of asking, Did anybody even look?

4. PMI has always spoke for itself. It will reveal every atomic element present without altering
or damaging anything. If a hidden ink was used, it’s atomic compounds could be detected. Add
Up with atoms are needed to make the ink, then add up which atoms are needed to make the
Paper. Add these together. Anything that deviated from that could be a special compound.
( invisible ink )

Such a great idea! Tom Voigt published high quality scans of the the Zodiac letters a while back, and the first thing you notice is that most of the pages have a weird diamond pattern on them. I’ve been afraid to ask, because I thought maybe it had something to do with the police analyzing them for fingerprints, and I never got around to searching the forums. A couple of examples with the contrast adjusted:

If Zodiac made the marks, it looks almost as if he painted something on the paper that ended up neutralizing the acids and kept those parts from browning with age. Googling invisible ink, one method that turns up is to use a paste made of baking soda and water as "ink," and to view the message, you would paint the paper with grape juice. I’m not a chemist, so forgive me if this is wrong, but the internet says baking soda is alkaline, and that made me wonder if maybe something similar were used.

Black lights were popular in the ’60s, and it would be absolutely amazing if Zodiac had left a hidden UV message in his letters. I really hope this is something that hasn’t been tried yet.

watermanrk?

Could he have been using some kind of light box and the diamond pattern is actually the shape of the light source? Don’t know why he would need it here but in the 340 cipher he might have needed it with some sort of grid over what he was tracing to keep everything edged up so neatly.

Could he have been using some kind of light box and the diamond pattern is actually the shape of the light source? Don’t know why he would need it here but in the 340 cipher he might have needed it with some sort of grid over what he was tracing to keep everything edged up so neatly.

Something like that could only be made by burning. This things looks very much likely chemical (or by the the industrial process as a watermark).
Exorsit letter have this thing too?

I don’t wanna beat the horse to death and ask about things that may have already been
done. But I’m going to anyway. I work in a testing lab and often wonder about the possibilities of
whether or not the tools I work with everyday may reveal more information about the letters.

Has the evidence in question (specifically the zodiac letters) been analyzed using
Digital Computed Radiography. This may sound stupid to some people, but I use this technology daily,
and I can say that this method is so sensitive to density changes that it can sometimes
differentiate between ink on top of other inks, latent impressions in paper you can’t see with
your eyes or take a pencil rubbing on., Even low density
inks printed on very thin plastic films can be revealed, in fact, this is
a problem for us at our lab we have to eliminate from time to time. We will see ink or
Non-visible impressions in our radiographs.
This method is nondestructive.

There is also PMI, (Xray Fluorescence). This could verify that the ink is in fact the ink
L.E. believes that it is, or if there is something else under the ink. It will identify every
atomic element in the ink and paper. This method is also nondestructive.

Surely somebody has at least exposed this evidence to ultraviolet, infrared light. (Any and all
available spectrums that won’t damage the material)
I also recall that spies/intelligence agents throughout somewhat recent history have used inks that can
only be revealed through application of very specific chemicals and must be in the
correct temperature range, PMI could very well reveal the presence of such
compounds used to do so. We may not be seeing everything that was written. That, or the writer left
something behind that we can’t see, something else that could be used.

I work in a testing lab in Portland, OR, so SF isn’t that far. I would love to help. Somebody should do this.
If nothing else to eliminate the possibility. Taking a look at things on a different spectrum often
reveals useful information.

You should contact with the police. Maybe you already did but if you still didn’t, we want to know what this can give us. Thank you for your info

Could he have been using some kind of light box and the diamond pattern is actually the shape of the light source? Don’t know why he would need it here but in the 340 cipher he might have needed it with some sort of grid over what he was tracing to keep everything edged up so neatly.

I guess it could be, I wish I knew more about chemistry and the paper he used. Something else to consider is that the same pattern seems to show up on the Phillips 66 map, which is way bigger than the letters. It’s harder to bring out by adjusting the contrast in Photoshop, but you can still make it out without even adjusting.

EDIT: I’m going to amend this. I’m not sure why I said "I guess it could be," because I actually believe 100% that he had a light box. Otherwise, creating the cyphers would’ve been a nightmare. Also the text of several letters are perfectly horizontal, which would be much easier with some sort of guide. Something that would be nice, is if we had very high quality scans of everything with something to show scale. I often wonder whether the 408, 340, and Phillips cyphers were written using the same guide, since they’re all 17 characters wide.

Close up of the lower left edge of the diamond:

Entire map with the contrast cranked up:

Exorsit letter have this thing too?

It does, and it’s a little bigger and more defined. It actually kind of looks more mechanical too:

I’d always assumed this was something well known, but I haven’t been able to find any other posts about the diamond patterns, so I’m just going to upload a few more examples. If anyone has any thoughts, I’d really like to hear them.

These were chosen randomly from some of the color scans I’ve been able to collect. The diamond pattern shows up on roughly 80-90% (edit: going through the letters, and I guess it’s more like 50-60%) of the letters, including the Phillips map posted above.

Could he have been using some kind of light box and the diamond pattern is actually the shape of the light source? Don’t know why he would need it here but in the 340 cipher he might have needed it with some sort of grid over what he was tracing to keep everything edged up so neatly.

He possibly had a light box because he was a draughtsman who made blueprints or other technical drawings.

Could he have been using some kind of light box and the diamond pattern is actually the shape of the light source? Don’t know why he would need it here but in the 340 cipher he might have needed it with some sort of grid over what he was tracing to keep everything edged up so neatly.

I guess it could be, I wish I knew more about chemistry and the paper he used. Something else to consider is that the same pattern seems to show up on the Phillips 66 map, which is way bigger than the letters. It’s harder to bring out by adjusting the contrast in Photoshop, but you can still make it out without even adjusting.

Close up of the lower left edge of the diamond:

Entire map with the contrast cranked up:

wowowowo, this is a really intereting thing to look carefully. Theres any hi res scan? The reverse is blank?

wowowowo, this is a really intereting thing to look carefully. Theres any hi res scan? The reverse is blank?

Yes, there is… I’m glad someone else feels the same way I do! I’ve been looking at this for ages, wondering why no one’s ever brought it up.

https://i.imgur.com/dS41WBm.jpg

EDIT: (sorry for the edits) There is a scan of the back side somewhere, but I don’t seem to have a copy of it.

Also, just want to add that an easy way to bring out the diamond patterns in the letters is to use Equalize in the Adjustments menu in Photoshop. I’m not a PS guru, and only just discovered that it works really well. I’d been using Levels and Curves before, which comes out too muddled. If I upload more, I’ll def be using equalize.