AgX Deep red sensitizer - cyanine CD-R dye

soda · Post by **soda** » Thu Jun 05, 2014 6:01 am

Hi everyone,
I'm trying DIY AgX chemistry for deep red pulsed holography (a happy owner of nice small ruby rod) and soon I found impossible to obtain cryptocyanine as other cyanines spectral sensitizers due to lack of some permission to handle with toxic chemicals. I start lookig for ewerything blue and green aroud me

and finally I found easily available deep red sensitizer - Taiyo Yuden cyanine CD-R dye! Prelimiary results are promissing, the dye - or micture of dyes - used as raw ethanol extract sensitizes AgX emulsion to deep red region, perfectly fit the ruby line and cheap 660nm diodes, moreover sensitize also a bit to He-Ne surprisingly. It seems to do not cause fog or desensitivation, even in excess concentration. Extraction is fast and easy: scratch a protecting layer near edge and using strong blast of air peel of complete reflecting layer, leaving PC substrate with dye layer. Aplying little of ethanol to the dye layer, it disolves quickly, producing the dye extract.
!!!! The dye is surely also toxic as other cyanines, despite easy availability !!!! It needs to be handled carefuly, avoid any contact with it!
Have a nice bright H's!

lobaz · Post by **lobaz** » Thu Jun 05, 2014 7:05 am

Wow!

a_k · Post by **a_k** » Thu Jun 05, 2014 7:50 am

Hello soda. Welcome to the forum and congrats for the success. I know the feeling when one is occupied intensly with a topic so much, that the perception of the surroundings gets modified in a way that suddenly everywhere items with a connection to the topic pop up. Do you say that you extract the blue dye from cd's (that's a clever inspiration i would say) or do you have a source for the dye. If you know a source, would you mind sharing it?

Ed Wesly · Post by **Ed Wesly** » Thu Jun 05, 2014 9:57 am

Absolutely genius!

holomaker · Post by **holomaker** » Thu Jun 05, 2014 10:08 am

a_k wrote: If you know a source, would you mind sharing it?

Please do, Fantastic!

dannybee · Post by **dannybee** » Thu Jun 05, 2014 1:23 pm

ooo i c what you doing, extrating the dye from cdr's .. very clever ,,,, I can see how this is a good find, it would probably be best to extract the dye from the lower write rate because that would have the most dye in the layer

soda · Post by **soda** » Fri Jun 06, 2014 3:26 am

Here is pic. of small test plate, just few drops of emulsion on 3x3 cm glass, intended for sensitivity testing. Only centre went well due to uneven thickness and processing, but it is evident that it works for holography!
My particular CD-R sample was quite old TDK CD-R74 48x, only little burned. Is seems that the same, or very similar, dye stuff is present in all CD-R produced by Taiyo Yuden, but it needs to be proven.
Wast majority of the dye extract was invested to spectroscopic measurement, but I still have enough dye for sensitivation approx. 1000cm2 - quite cheap source of sensitizer.
Spectral absorption of heavily dye over-doped plate shows that the extract probably contains micture of two similar dyes which perfectly match to all red laser lines.
While looking for new CD-R sample, I found that majority of CD's are AZO or Ptalocyanine, only small part is the desired Cyanine types reselled here in Europe as Verbatim, JVC and TDK. I also found that Taio Yuden produce DVD's - if it contains cyanine, it perhaps match to green lines. It sounds like a joke to produce panchromatic emulsion ot of CD/DVD extracts...

a_k · Post by **a_k** » Fri Jun 06, 2014 3:39 am

That looks like a hologram with a high diffraction efficiency to me. Was it made using the ruby laser you mentioned or was a different light source used? Can you give an estimation of the sensitivity or the intensity/exposure times used?

Do you need for your emulsions a similar amount of dye as on the CD? The 1000cm2 of remaining dyes stock you mentioned is worth how many CDs?

a_k · Post by **a_k** » Fri Jun 06, 2014 3:41 am

And i like that beautiful golden colour. Is the colour representation on the picture about correct?

soda · Post by **soda** » Fri Jun 06, 2014 4:13 am

a_k: Ruby is still uder construction, He-Ne laser was been used and due to processing in OD-1 and fix shifted to this nice yelow-green colour. But color representation is not trully correct, this picture was taken under ordinary room light plus an yellowish LED, in sunshine it is more green. Using the ruby I suppose to result in little more orange tint.

I extracted only ONE CD-R, the dye stuff is pretty efective - one CD should be enough for several thousands cm2. Sensitivity of my crude emulsion is low, exposure was approx 25mJ/cm2. But problem is not spectral sensitivation, overall sensitivity of my emulsion is still low, sensitivity is comparable to blue light and sensitivation by R6G for green is many times worse. Perhaps due to large halide excess and lack of chemical sensitivation.