Do It Yourself Ground Glass

A couple weekends ago I went and visited NYC. What started out as a trip to visit a friend who moved there a few months before ended as a journey to bring home a new (old) camera. It began one day while searching through the 8x10 camera listings on eBay. I never really thought that I would buy one, especially since I already had plans to build one. But, as the process advanced and I continued to draw up and change plans, I thought it would be helpful to look at a finished camera in order to better understand how the gears were set up and how the knobs moved and tightened different parts of the camera. I found a beautiful old Gundlach Korona on the Bay, and I added it to my watch list. Days later it was ending and in a spur of the moment decision, with 6 second left, I tossed in a bid. I was bidding on my phone, and the page told me it was sending my bid, but I was nervous that it might not go through in time. When it finally refreshed, it said the item had ended and I was the high bidder. I was immediately filled with mixed feelings: did I really need this camera? Did I really just spend that much on a camera? And, mostly, what the hell was I thinking?

Long story short, the seller was located in Brooklyn, NY, and since I already had plans to visit that weekend (the listing ended on a Tuesday night) I asked if I could meet him somewhere and pick it up to save myself the cost of shipping and to save him the trouble of trying to safely package it and get it to a post office. After a couple changes in plans while there, I eventually picked it up and fell in love immediately. It was a wooden goddess.


The only problem with the camera was that it didn't have a piece of ground glass in the 8x10 back. For anyone who doesn't have experience with large format cameras, the ground glass is a piece of frosted glass that the image is focused on before burning it into the film. It is 100% necessary, so I had to either buy a piece of glass or somehow make a new one. Buying one would mean going on eBay and spending a minimum of $70. And to me, spending that much for a piece of glass just seemed ridiculous so I started researching how to make my own. One of the first websites that I was directed to was an APUG (Analog Photography Users Group) thread that was basically a step by step process of how to make one using Silicon Carbide grit and any old piece of glass. I recently threw away a pile of old picture frames and had saved the glass (I was thinking of starting wet plate, but that's on hold for now) so I made sure it would fit the back. It was perfect. I clipped the corners and it was ready.


I found the Silicon Carbide grits from a company called Kingsley North Inc. after searching on Google for Lapidary supplies (the silicon carbide is also used for sanding and smoothing stone/gravel). I decided to get both sizes recommended on the APUG thread (400 and 600) because the piece of glass was so large and I wanted the finish to be as fine as possible. The only downside to ordering was that it only came in 1 pound boxes; it ended up being so much more than necessary to make a single ground glass. It cost me $21 for the two pounds and shipping (the grit was only $4.85 for each box and the shipping was the rest). Days later, a package arrived in the mail.

Aside from the silicon carbide grit, the only other things that are necessary to make the ground glass are a cup of water (I didn't have a cup on hand so I used a small stainless steel developing tank - it seemed more fitting anyway), some wet/dry sandpaper to smooth out any rough edges on the glass, and a smaller square of glass to use as a grinding tool. It is very important that all the edges of the grinding piece (mine was approximately 3x3 inches) are extremely smooth so that it doesn't scratch the ground glass as you are spreading the grit.

I am going to assume that the amount of grit that you place on the glass is completely up to the person doing it, so I sprinkled a little onto the surface and sprayed a bit of water on. Make sure that there is enough water, otherwise the grit is much too rough to spread. The process reminded my of playing in the sand on a beach - not enough water and it wasn't usable, but too much and it was just runny and also unusable. Use the 400 grit first to lay down a base layer. After grinding for a couple minutes, I added a little more grit and a little more water to give a second coat. After about 4-5 minutes you should completely wash everything off the glass, front and back, and then dry it fully. Do the same to the smaller grinding piece.

As you dry off the surface, you will notice that the surface will begin to appear frosted. This is a good sign. I'm not exactly sure why it looks transparent when wet and much less so when dry, but it's really neat. After the glass is completely dry, sprinkle on the 600 grit and add water. Grind it in the same manner as previously stated, adding a second sprinkle and more water after a couple minutes. In my case, there were a couple areas that weren't fully covered after the 400 grit so I made sure to get those areas with the 600 so it was as even as possible. After 4-5 minutes with the 600 grit, I washed it off and dried it. Holding it up to the light, it was very even, and looked good enough to use.

I was so excited to see if it worked in my camera, so I loaded it into the 8x10 back. It looked as though it 100% belonged there and it gave me a real feeling of pride that I had done such great work on it.

It was dark out so I couldn't take the camera outside to see how it worked, so I just attached the back and set it up in my living room. It looked good, and seemed bright enough. The next morning I set up the camera and pointed it out the window into the daylight. I was so happy; it looked amazing. Here's what I saw:

All in all, it took me less than an hour to do everything, and cost me less than $30. That's already a more than 50% savings over what a ground glass would cost, and I have enough materials to make at least 8 more (that's how many pieces of glass I have left). There is probably enough grit left to make at least 25 more in the 8x10 size. More in 4x5.

The next step is to CLA the lens - I'll be working on that today and tomorrow. After that, the camera should be more than ready to get out into the world.

And no, I haven't given up on making my own camera. The plans are still in the works, and the more I play with this camera, the more I understand exactly how it works. It also gives me ideas of things I can change to make it more user friendly. Well, here goes nothing.

I learned everything here so if you have any questions or if I missed anything, the APUG thread might be helpful to look at: http://www.apug.org/forums/forum216/78392-making-ground-glass-focus-screen.html