My Mobile Darkroom For Platinum & Silver Gelatin Contact Printing

April 16, 2017  •  Leave a Comment

Developing film in my mobile darkroomDeveloping film in my mobile darkroom I thought I would share some information with my readers about how I have tackled the process of developing my large format sheet film on the road and how I make my pure platinum prints when I am away from my darkroom. 


Before I share how I am able to develop large format sheet film on the road and make platinum contact prints, I thought I would discuss some of my key motivations for wanting to do this.  

Many of my subjects are located hundreds, and in some cases, thousands of miles from my home.  Since I use large format view cameras and sheet film, I need to know that I have proper negatives before I depart the location.  Leaving without securing negatives suitable for creating my prints would be a costly and disappointing mistake.  

When I began this journey, my primary goal was to just develop the negatives in the field and then return back to my darkroom for making the platinum prints.  While I still do this, I wanted to work through the obstacles to make platinum prints on the road in my Sprinter van.  I find that I have a desire to stay out in the field longer and I am able to make adjustments that I would otherwise not be able to do.  For example, if I make a print and I think that I would like to modify the composition, I can simply stay another day and purse that and see how it goes.  

Another benefit is the ability to stay busy in between the good light.  I normally only create exposures in early morning or late afternoon light, so that leaves the bulk of the day open.  Many times, I use that time for scouting, taking a hike, or just relaxing, or even a much needed nap!  I like the option to use that time to develop film and make prints.  Then when I get home and back to my full size darkroom, I can relax and evaluate the prints more closely and then pursue making more prints based on the field versions.  I like having time in between printing because I use this reflective time as an opportunity that helps me create better prints.  I also feel like I accomplished a lot more on my trip versus offloading all of the developing and printing post the trip.  For whatever reason, I just feel better about things from working like this.  


My DIY film development tubesMy DIY film development tubes Historically, I developed all of my large format sheet film negatives with a Jobo processor.  I use a CPE-2 processor in my darkroom for a variety of darkroom related work ranging from developing black and white film, to color negative C-41, E-6, and even RA-4 color prints.  The Jobo processor is a versatile tool that can assist the darkroom photographer with a lot of different tasks.  Many years ago, I acquired a smaller processor, the CPP-2 for my mobile processing up to 8x10 film and prints.  Controlling light, meaning eliminating it, can be real challenge when working mobile. The Jobo processor can really help eliminate most of those challenges after you get the film or paper loaded into the processing drums in your dark tent.  

I recently changed from developing negatives for my platinum prints in the Jobo processor to a semi-stand process using home-made PVC tubes.  The underlying reasons for this are beyond the scope of this specific article, but, I can tell you I would not modify a long-standing process unless it was worth the angst and effort.  

Long story short, my process for developing film on the road in my small Jobo CPE-2 is no longer an option for me.  I didn't explicitly state this, but one of the advantages of using a Jobo processor is temperature management.  My film development is tuned for 21C/70F, and while I can modify variables and adjust the development time, I try and avoid that if I can.  

To address the temperature management issue, I found a used Jobo TBE-2, which is a tempering bath.  It is more or less a Jobo processor, without the film processing capabilities.  The TBE-2 comes in a few different configurations.  I went with the smallest version that I could find to conserve space without sacrificing any functionality.  Like the image to the left, my unit has the ability to temper six one liter canisters and six 260ml at the same time. Depending on the size of film I am developing, I usually can get away with one slot for my Pyrocat HD developer, one for my stop bath, and the third for my TF-4 fixer.  I wrote an article about switching to TF-4 fixer that you may want to review.  This choice has simplified my workflow drastically and this really helps when doing all of this mobile be reducing the number of chemicals that I have to manage.  

Another benefit of the TBE-2 is the ability to stand my development tubes in the waterbath if I need to do this for temperature management on long development cycles.  I have onboard solar power in my Sprinter van, and this allows me to power the TBE-2 via solar energy.  I do keep a generator on hand in the event I need more power than I can generate via solar.  

I keep a dark tent on hand to transfer the film from my holders to my development tubes before I begin the development process.  The tent is collapsable and I can easily store it with very little space requirements. I also have a brand new custom-made mobile darkroom box that I use as well.  

I have the film development issue under control and so now I will move onto the more difficult matter of making the platinum prints.  


The more difficult issue is exposing and developing my platinum prints while mobile in my Sprinter van.  I take a traditional approach to making my platinum prints.  I use ferric oxalate and platinum salts to create my sensitizer and I use potassium oxalate as my developer with potassium dichromate as my restrainer (contrast management).  While it is technically possible to expose platinum prints with sunlight, it isn't a reliable exposure method for making fine prints.  I designed and built a custom UV exposure unit that is small and portable.  

Warming Potassium Oxalate developer for my platinum printWarming Potassium Oxalate developer for my platinum printYou may also enjoy my free darkroom photography newsletter and my magazine, The Darkroom Underground, devoted exclusively to analog photography covering a balance of technical and creative topics. The exposure is only half of the battle for me.  I vary the temperature of my developer to get the special look I want in my platinum prints.  By controlling some specific variables in my process, I am able to get warmer tones in my pure platinum prints that are often associated with adding palladium to the sensitizer.  

I must have the ability to warm my developer, so this means I need a heating solution that can be powered while mobile.  I have a laboratory grade heating unit that is also has a temperature probe for heat management and it is has a mixing function which I use when making emulsions from raw chemicals.  


All of the major obstacles to creating handmade artist original platinum prints while mobile have been addressed.  Sometimes, depending on environmental variables, it can be difficult to manage all of this, but it is doable most of the time.  

As long as I work in subdued light, everything in my process except for the film development process up to the stop bath is easily managed.  For the parts of my process that requires total darkness, I custom designed and built a collapsable portable darkroom (see photo at top of this article).  

I started with a wardrobe cardboard box many years ago, then I reinforced the inside of the dark box with thin sheets of plywood.  The second generation box is actually still a very viable and effective solution.  I needed a new solution that took up less space and so I designed and built my newest and hopefully final portable darkroom.  During the film development steps that requires me to remove the lid and pour in the water, developer, and stop bath, I need to perform these steps inside the mobile darkroom so that I don't fog my films.  After I get through the stop bath, I am able to fix the film in open trays in subdued light.  

My mobile darkroomMy mobile darkroom I needed more from my mobile darkroom, than just being a mobile and reliable dark space.  Instead of offering a low-cost digital reproduction print alternative to my platinum print for my collectors, I keep my workflow completely analog and create silver gelatin contact prints.  

I am continuing to work through the process of creating a single negative that will allow me to create a platinum print and a silver gelatin print, however the longer tonal scale for the platinum process requires a negative not normally suitable for silver gelatin printing.  I am trying to leverage the benefits of Pyrocat HD developer and its staining capabilities for this.  This is a work in process and while it is not a priority for me, I would like to get this worked out over the long term.  

I also installed a light source on the top center of my mobile darkroom that acts as an exposure light source for my silver gelatin contact prints.  Then I develop, stop, and fix these prints inside the box too.  

I hope by sharing my mobile process with readers that it may inspire other photographers to take their creatively on the road.  In the age of all things digital, some people might ask, why go to all this trouble when you could just use a digital camera and eliminate all of these obstacles?  My response is simple...I don't want to do that, I want to keep my creative workflow entirely analog.  

I have tested the creation of digital negatives using Pictorico film using Photoshop and an inkjet printer and I found this process to be very expensive (new computers, Photoshop, inkjet printers, etc).  I would rather use that money to travel to new places.  Large format is my secret weapon and film is the x factor that makes my prints stand out.  

-Tim Layton 

The Darkroom Underground is your analog photography magazine produced on a quarterly basis serving photographers, artists, collectors, and readers around the world.  The Darkroom Underground publishes a balance of technical and creative articles in every issue along with featured photographers and their portfolios. We are pleased to offer editorial from internationally recognized photographers and writers and also publish articles and portfolios from our readers. 

If you like this type of article then you will probably enjoy my free darkroom newsletter and my darkroom and large format video-based workshops

Tim Layton
B&W Fine Art Analog Photography
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