RA4 Print Developer & Blix Formulae

Hi to those who are fellow color darkroom enthusiasts,

I added a couple new technical pages to my site. The first has formulae for RA4 roller

transport compatible Developer and Blix. If you are tired of having commercial kits go bad

in storage, or simply having a hard time getting kits because your local camera store has

become a computer and peripheral shop, see: <a href="http://

www.people.fas.harvard.edu/~keirst/technical.html">http://www.people.fas.harvard.edu/

~keirst/technical.html</a><br><br>

Also I have a second page for Jonas Palm's Room Temp RA4 developer from which I

derived my formula. See: <a href="http://www.people.fas.harvard.edu/~keirst/technical-

jp-dev.html">http://www.people.fas.harvard.edu/~keirst/technical-jp-dev.html</a> for

his original recipe. I have not actually tried it because I have a roller transport processor,

and so I don't do any development at room temp.<br><br>

Most of the chemicals are available from <a href="http://

www.artcraftchemicals.com/">Artcraft Chemicals</a>. I get Etidronic acid,

Diethylhydroxylamine and Triethanolamine from <a href="http://

www.sigmaaldrich.com/">Sigma-Aldrich Chemicals</a>.<br><br>

Please take some time to look at newly posted photos on my revised site at: <a

href="http://www.people.fas.harvard.edu/~keirst/">http://www.people.fas.harvard.edu/

~keirst/</a><div></div>

Steven,

there are some really nice photos on your website and I really like those b/w snow photos in the 'Boston' section. Your 'photojournalism' section also provides us with a nice look into the current state of American society. I've always been fascinated by the fact that the moral issue that is adressed by these people, can stir up emotions so much in your country, it's a complete contrast from where I live (Netherlands).

Anyway, there are some really nice shots on your website, maybe you can provide your viewers with some technical info when you upload new photos in the future.

Juergen

Steven;

The use of CD4 for the color developing agent will severly degrade dye stability of your Endura and Crystal Archive prints. In addition, the more polar dyes formed will have broader, more hypsochromic absorption and therefore will not have the high saturation that they would have in CD3 developer.

This was discussed by Pat Dignan, many years ago, in his newsletter and has been well known for years.

What is less well known is that the EK RA developer replenisher and blix can be used as low as 68 degrees F with excellent results. I have been doing this routinely for years.

I truly hope that no one uses the 'room temperature' developer posted at that URL.

In addition, the formula for the regular RA developer is not correct. It uses the wrong chemistry and can lead to poor curve shape. Two required ingredients are missing completely.

Good try, but no cigar guys.

I suggest that you include information on precise pH for the developer and blix. They are critical. If blix pH is wrong, you can have problems. It should never be acid enough to replace the stop bath. The pH should never be lower than about 6.3, but I prefer 6.5.

In addition, the special prewet is not needed. You can use plain water. And, the stop bath is usually 2% acetic acid not 3% - 5% acetic acid.

Ron Mowrey

OK Ron, I'm not a chemist. What two more ingrdients are needed to make my RA4

developer "complete". What is their function and what adverse affects are caused be

leaving them out? As my webpage says, I do not use CD4, and I included Dr. Jonas Palm's

formula to indicate where I started from.

See <a href="http://www.people.fas.harvard.edu/~keirst/technical.html">http://

www.people.fas.harvard.edu/~keirst/technical.html</a> for a newer formula that provides

good results. I probably will be working on it some more in the fall when it coold down

enough for me to get in the darkroom. I may be adding 1g/L potassium sulfite to the new

mix.

Looking better and better.

Just watch out for potassium sulfite. Dmax and contrast will go down rapidly as you add more and more of it. Also, potassium ion can interfere with fixing.

And STAY AWAY FROM CD4 WITH COLOR PAPER.

Ron Mowrey