Our darkroom is in its 3rd incarnation as a central part of our business. It is quite large now and the entire room humidity and temperature is controlled to produce a precise hydration for our platinum / palladium printing. By controlling the hydration of the paper both before and after coating the sensitizer we are able to precisely control the process with PiezoDN - with no need for proofing or test prints as the results match our displays.
The sink is 40" x 12’ and made of stainless steel fabricated by a local sheet metal company that specializes in dairy farm sinks. The costs were 1/8th that of what was quoted by a darkroom sink company. I highly recommend going to a local dairy farm and asking where they have their massive sinks made. It is a different economy than the darkroom suppliers… yet the same stainless steel and same concept of slow movement to a drain.
And we now develop and build the world’s fastest UV Exposure systems. Our fastest system, now in place at dozens of others studios and Universities can expose a platinum print in 60 seconds. That innovation helps produce smoother prints with better dMax.
The darkroom can accommodate 6-8 workshop attendees - so it is much larger than one would need as a personal darkroom… but the concept of controlling hydration should be the same. Running a humidifier, a dehumidifier, and a temperature controller all triggered by digital control systems is the secret to producing platinum prints that match your intentions. The process of noble metal salts converting back to the actual metals is regulated by the presence of water molecules. And precise relative humidity is the most overlooked factor even by seasoned practitioners. We use inexpensive digital controllers where we set a range of temperature and humidity to remain constant within +/- 1.5 degrees. Beyond that we measure contrast changes which are unwanted.
The darkroom ambient lighting is produced by LED relatively free of UV and is like the dimness of what an imaging room should be. Actually a bit brighter - so we can work in a natural feeling environment rather than a “dark” room. WE have recently applied three layers of UV blocking film to one of our picture windows and it removes more than 97% of the UV. One layer advertised as 99.3% removed only 50% (apparently buyers of these products do not measure for 365nM). So now we work able to see outside and long days are more than pleasant.
Our verifiedUV exposure system is fully enclosed so that we can expose where we coat and with the entire darkroom humidity/temperature controlled we can coat where we expose and also sink process. The a/c slash heat, dehumidier, and humidifiers all turn on and off as needed by the digital controllers.
That’s the state of our darkroom and easy to replicate. The most important being this particular device: Amazon.com: WILLHI WH1436H Mini Plug-n-play Digital Air Humidity Controller with probe for Humidifier Dehumidifier Greenhouse Pets Animal Basement : Appliances
In terms of our chemistry - I transitioned a few years ago from potassium based platinum / palladium to Malde-Ware. Potassium based required ferric oxalate which I find to be the bane of anyone’s existence in a darkroom. Malde-Ware introduced to me by Pradip Malde is infinitely more stable because it is ammonium based. We can mix our noble metals with ammonium ferric oxalate and the mixture stays fresh and sensitive for up to 4 years in an amber bottle. So, we tend to calibrate a 25-200ml bottle of sensitizer and set and forget… as long as the relative humidity is controlled and we use the same bottle we do not need to recalibrate or count drops and all that. We also keep the same batch of Revere Platinum paper and a single batch of Arches Platine to eliminate variables.
We calibrate differently in the Summer than in the Winter because it is easier and more efficient to control 57-60% rH at 72ƒ in the winter and 63-65% rH at 68ƒ in the Summer. These produce two different tones in the final prints but we can also change tone through mixture of platinum to palladium. We tend to a 50/50 mixture unless a client wants something “special” such as very warm brown or very cool neutral…
We can turn on our relative humidity controllers on Saturday and by Monday morning we simply need print film and produce finished prints. This control via relative humidity and PiezoDN allows us to produce, for example, five perfect 22x30 prints without having to make a single test print… Our system works for us professionally and economically and most importantly matches our intentions.
Initially - with the potassium based chemistry, and fair to say before we controlled the environment, what came out in the tray was a total mystery with ferric oxalate. And while that is magically interesting it is also quite expensive. Rather than rely on mystery to control what our prints look like we can now rely 100% on our displays. We have had workshop attendees (we offer these in the Summer) who have taken this humidity control to bathroom sized darkrooms and have reported the same control. We are also the only source of Malde-Ware authorized pre-mixed chemistry and we produce it differently than other suppliers. We offer bottles of pre-sensitized solutions that can be used for years. Our customers can also calibrate their darkrooms with our PiezoDN system and enjoy the same consistency that we do. This is what we teach in our workshops!
So there is the update!
cheers!
Jon