I often get asked if coating ultra-large plates—like the impressive 20×24 inch pieces—is much harder than coating smaller ones. The answer? It’s both yes and no.
When you’re working on a plate of this size, every step of the process demands extra practice and precision. Spreading emulsion evenly across such a vast surface isn’t as simple as it sounds. For instance, using a syringe coating technique means you might need to stop and refill your emulsion cup three or four times while maintaining a perfectly level plate to avoid messy spills. On the flip side, the substantial weight of these plates can actually help you stabilize them with your fingers, provided the plate isn’t excessively heavy. Still, any spill on such a large canvas can be costly, both in wasted materials and time.
The Challenges of Coating Ultra-Large Plates
Coating larger plates comes with unique hurdles:
- Precision and Practice: Achieving an even emulsion spread over a 20×24 inch surface takes considerable skill.
- Multiple Refills: With a syringe technique, you’ll likely need to refill your emulsion cup multiple times—each refill is a potential risk for spills.
- Managing Spills: A spill isn’t just a minor hiccup; it can mean a significant loss of both material and work time.
Expert Tips for Success
Here are my valuable tips for coating big plates:
- Use Thicker Glass: For plates larger than 8×10 inches, opt for 3mm glass or thicker. This ensures better support during the coating process.
- Choose the Right Drying Space: Work in a dark, well-ventilated area. A dedicated drying cabinet or even a well-set-up counter in your darkroom can make a huge difference.
- Protect Your Workspace: Spills are almost inevitable. Cover your work area with newspapers or protective sheets to minimize cleanup.
- Prepare in Advance: Have plenty of melted emulsion ready. Running out midway can disrupt your flow and lead to uneven coating.
- Select the Right Syringe: I typically work with a 20ml syringe. Although larger syringes mean fewer refills, they can be more challenging to control.
- Keep Everything Warm: Ensure that both your work area and the plate are warm. Using a hairdryer or heating pad helps prevent the emulsion from setting prematurely on one end.
- Stay Focused: Once you start coating, work quickly and methodically. There isn’t much time to spare, so staying focused is key to success.
Pushing the Boundaries: Beyond Hand-Coating
From my experience, 20×24 inches is about the maximum size you can effectively coat by hand. For plates larger than this, you might need to explore alternative solutions. For example, laying the plate over a dish tray heater (or several heaters) can help keep it warm during the process. This method, however, brings its own set of challenges—maintaining a level surface and managing excess emulsion can become trickier.
Final Thoughts
If you’re eager to venture into coating these ultra-large plates, start with smaller sizes first. Embrace the learning curve—even expensive failures are valuable lessons in perfecting your technique. Remember, the art of plate coating isn’t just about the act of coating; it also involves thoughtful planning around drying, storing, and ultimately exposing the finished piece.
Mastering the art of coating ultra-large plates is a blend of technical skill, creative problem-solving, and a willingness to learn from every mistake. With patience and practice, you can elevate your craft and achieve beautifully even coatings on even the most challenging surfaces.