There’s something incredibly satisfying about finally seeing clean, neutral and bright positives appear on the plate in fixer exactly the way you imagined them.

If you’ve worked with direct dry plate positives for any length of time, you’ll know that this has always been one of the most elusive parts of the process. Not sharpness, not contrast, but white balance  that delicate, silvery neutrality that gives a tintype its unmistakable presence.

And this is exactly where things have just taken a big step forward.

Tested Where It Matters In Real Workshops

Over the past months, I’ve had the chance to test a new complexing agent not just in controlled conditions, but where it really counts, during multiple private workshops.

And honestly, that’s been the most exciting part.

Because for once, I’m not just producing plates for others, I finally get to use them, experiment with them, and really understand how they behave in practice. No matter how many you expose your learn something new every time! 😀

Each workshop became a true testing ground. Different lighting setups, different exposures, different hands working the same chemistry. And through all of this, one thing became very clear, we were getting closer to consistent, neutral whites than ever before.

The Challenge We All Know

For years, direct positives on Zebra Dry Plates have relied on Ammonium thiocyanate.

It works, and it made this whole process possible. But it also comes with a very familiar challenge.

The development stage is a delicate balance between:

• exposure
• developer
• complexing agent

Even when everything is carefully dialed in, achieving stable white balance and clean highlights can still feel unpredictable. Whites shift between warm and cold tones, sometimes beautifully, but rarely consistently. That neutral silver look we’re all chasing has always required patience, experience, and often a bit of luck.

A Better Way Forward

This is where Potassium thiocyanate comes in.

Originally introduced as an alternative, it quickly proved to be something much more important, a refinement of the entire process.

Used in combination with HC developer, it works by dissolving and redepositing silver onto the plate’s surface, transforming the negative into a direct positive image. But unlike the traditional approach, the reaction feels calmer, more controlled, and far less prone to sudden shifts.

What you start to notice is not just a difference, but a shift in confidence while working.

• Whites appear brighter and cleaner
• Tonal transitions feel smoother
• The overall image structure becomes more even
• White balance is significantly more consistent

What You’ll Notice in Practice

The difference becomes especially clear when you compare results side by side.

A well-processed plate using ammonium thiocyanate can still show slight color shifts and uneven highlights, even when everything is technically correct. Next to it, a plate processed with potassium thiocyanate feels more stable, more resolved.

The whites are not just brighter, they are cleaner. The image carries a more balanced, almost refined presence, closer to that neutral silver tone we’ve all been aiming for.

And perhaps most importantly, the result becomes repeatable. Not perfect every time, but far more predictable.

A Simple Starting Point

For those who want to try it, here is a reliable starting formula:

For HC-110 users:

• 2.5 ml HC-110
• 1.5 g Potassium Thiocyanate
• 300 ml water
• Development time around 4 minutes at 20-21C

For Pyro users:

• 2ml 510 Pyro
• 1.5 g Potassium Thiocyanate
• 300 ml water
• Development time around 4 minutes at 20-21C

From there, you can adjust based on your own workflow, lighting conditions, and desired look. The beauty of this approach is that it gives you stability without removing creative control.

Efficiency and Stability

Another aspect that quickly becomes apparent is efficiency.

The process requires smaller quantities to achieve strong results, while also reducing common issues like uneven bleaching or solarisation. It simply behaves in a more predictable way, which makes a big difference when you are working in real conditions rather than controlled tests.

It’s not just about better results, it’s about a smoother workflow.

A Workshop to Remember

One of the highlights of this journey was a private workshop with Jaques Pion, who came to learn how to create one-of-a-kind direct positive portraits for his artistic and gallery work.

We spent two fantastic days together going through the entire process, from coating plates from scratch, to studio exposure, and finally to processing direct positives. It was the perfect environment to push this new chemistry further, and once again it proved itself as a clear step forward.

A special thank you goes to Peter from Primer Cameras for allowing us to use his space and the beautiful Primer 8×10 / 10×10 camera. Working with such a camera adds a completely different level to the experience and made those two days even more memorable.

And Jaques, thank you for the curiosity, the enthusiasm, and the great company throughout the workshop.

Learn It Yourself

If this is something you’ve been curious about, especially if you want to explore direct positives more seriously, this is exactly what we focus on in private dry plate workshops.

From raw glass to a finished positive, from theory to hands-on practice, the goal is always the same, to give you control over the process and confidence in your results. And now, with a more stable and predictable approach, it becomes even more accessible.

What’s Next

We will continue to refine this further. Testing different developers, exploring variations, and pushing the process toward even greater consistency.

The long-term goal is to simplify things even more, possibly into a single or A+B solution that you can just mix and use without overthinking the chemistry.

But for now, we are incredibly excited to introduce potassium thiocyanate into the workflow.

Let’s Improve It Together

As always, this process grows through shared experience.

If you start working with it, I would love to hear your results, your timings, and your approach. Because with each plate and each variation, we move one step closer to mastering something that has always been beautifully complex.

Direct dry plate positives have always been special.
Now they are finally becoming consistent as well.

And those clean, balanced whites are no longer something you chase, but something you can reliably achieve.