Enlarging onto AZO using my LED HEAD

[huw_finney]

This I posted on the AZO forum after someone kindly donated a few

sheets of AZO to play with.

 

The test as been done...

 

Conditions:

x4 linear enlargement, developed in Ilford MG for two minutes.

Lens at f4

12x1W LEDs royal blue lumileds luxeon emitters

 

Result:

8 minutes for a full black from clear negative portions.

4 minutes the blacks a bit grey.

 

Conclusion:

An enlarging head for AZO using LEDs is practical.

 

How:

Double the number to 24, and use 3W emitters, 5W ones exist

but are disproprtioatly expensive.

Projected result:

For a 4x (linear) enlargement at f8 you will get about

5 minutes exposure, for 2x (linear) about 45 seconds.

 

Huw

[douglas_price]

I thought you couldn't enlarge onto AZO. I was wondering why, as no reason was ever given. From what I've seen of AZO, I wish I had the facilities to try it myself. I take it the LED head is crucial, because of the blue only sensitivity of AZO, and a standard head wouldn't work?

Assuming I could manage to scrape together an enlarger and some trays, would a color head, or blue filtration on a standard head help me? What about the cost of building an LED head? (I'm proficient enough in soldering)

 

This is really interesting news :)

[huw_finney]

Tungsen light has very little blue in it especialy at the short end. LEDs are not as bright but (for the blue ones) it is all blue. No point in filtering the light AZO only reacts to the blue section. To my knowledge two heads have been built so far, take a look at my website huws.org.uk

[henry_a]

I have one of Huw's LED heads. It works -- wonderfully -- for standard enlarging papers, giving me variable contrast with constant exposure times by just turning a dial. I have no doubt that Huw can carry his expertise over to Azo enlarging.

[davidv1]

Huw,

 

Have you seen the OptiLED Festival (or Festoon) lights?

 

http://www.optiled.biz/products/products.html

 

Their blue is the same 455 nm wavelength as the Luxeon Royal Blue. I can't tell how bright they are compared to the Luxeons, though.

 

Do you suppose a simpler model enlarger head could be built around one or more of the blue OptiLEDs?

 

Thanks, David

[brian_ellis16]

I don't mean to rain on anybody's parade but hasn't Azo been discontinued along with all of Kodak's other b&w papers?

[neil_miller2]

Brian's right - on the Apug and Azo forums Michael A. Smith has explained that kodak have sold all the remaining stock to a few individuals and that production has ceased. Michael has stopped selling and is - sensibly - keeping the rest of his stock, I think, while he sources another silver chloride paper. I have been told that a few places still have g2 Azo, but for some reason g3 is preferred, most people saying that g2 should be used for proofs.

 

I expect that the new silver chloride paper Michael is testing or developing (no pun intended!) will share the same characteristics of Azo, but inevitably there must be differences, so sadly Azo seems destined to become another folk-legend quite soon.

 

Regards,

Neil.

[martin_pistor]

Hi Huw,

after reading your page, I did my own tests with a point light source, saying one RBl 5W Luxeon and 4Gn 5W around it.

In my Durst 139 they blew all a 300W Opal lamp showed, unfortunately only the RBl one (hard). This was perfect for Lith-printing and for Negs and scale, that show strong grain.

your Post means, I could try Cyanotype with this too, doesn't it?

I'll just try and post the results.

Regards,

Martin

[michael_briggs2]

Azo is definitely ending, but isn't completely gone yet. Unless there is a latter announcement, the situation of the seller Michael A. Smith isn't that he has stopped selling all Azo paper -- he has stopped selling grade 3, but still has some grade 2. See http://www.michaelandpaula.com/mp/AzoForum/one.asp?ID=8621&PgNo=&GID=8621&CID=7

[henry_a]

David,

 

I use the Festival OptiLed lamps in red and red/orange as safelights. They do not seem as bright as Huw's leds but it would be a simple thing to try for a large format enlarger. Maybe four sockets mounted on a board with four Festival blue lamps would make a good light source for blue sensitive material printing?

 

My "MP VariBulb v2" (yes it has a name!) that Huw made for me has bare blue and green leds glued to an aluminum plate which I housed in a white painted tube with a diffuser a couple of inches away - a mixing chamber if you will. The 2 colors or wavelengths of light mix quite well this way giving even coverage and I can vary contrast as I choose. Of course there's more to it than this - some fairly serious magic happens in the control box. But the reason I'm telling you this is that the festival lamps are physically large and I don't think you can get enough of them situated together to mix two colors of light, but I could be wrong. With one color you might pull it off.

 

I would very much like to hear what you get if you try this route.