Copy Stand

[eldon]

I am trying to find replacement bulbs for this vintage Clarkson copy stand. the original bulbs make everything orange. i assume they ate very old and the color temperature has shifted. Any help is appreciated. Thanks. See pictures below.

 

[jlafferty]

Search the text on the base. I'm seeing this:

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www.bulbconnection.com

You can prob find an LED replacement if you like.

 

[eldon]

Tank you for the quick response. I kept coming up with automotive bulbs when I searched. I will look up the bulb you recommended.

 

[jlafferty]

Tank you for the quick response. I kept coming up with automotive bulbs when I searched. I will look up the bulb you recommended.

That’s probably fine, too. You just need to figure out the name of the connection type and the power draw and you’ll sometimes find these bulbs are used in all sorts of scenarios.

 

[eldon]

Thanks again. Time for me to do some more research. This copy stand is ancient, but I think I have the original owners manual somewhere. I could not find any reference to it online. Great responses to my question. I always get quick results from this site.

 

[Ellis Vener]

If you are using film, you need to use a tungsten balanced film stock or an 80A filter.

if using digital change your white balance setting to 2700K. But a better solution would be to purchase an 8x12 inch Calibrite ColorChecker or even better a Calibrite ColorChecker Passport II Target set and use the free Calibrite profiling software and create a custom profile for your camera. You can also use either of these targets to make profiles for other cameras or other types of lighting.



the COLORchecker Passport II target set also contains two non-metamerising gray card targets which you can use as white balance references or to see a custom white balance for your camera.

 

[eldon]

Thank you for your response. Sorry it took so long to reply, but for some reason I did not get a notification. I just purchased a Canon EOS r7 camera. I do have gray cards and I know I have a color checker card buried somewhere. I will look into your suggestions.in reviewing my camera's white balance settings, I can set a custom balance to 2400 K and above. My last digital camera was an Olympus E20N so I have a lot to learn.

 

[Hanson Peterson]

Tank you for the quick response. I kept coming up with automotive bulbs when I searched. I will look up the bulb you recommended.

The results say it's an automotive bulb, because it is. That bayonet style has been used on millions of cars, for turn signal, brake, and reverse lights.

Also, if you're getting orange color, I wonder if it's not the bulbs but the power supply, oxidized or deformed bulb contacts, or slackened spring-steel connections (the sockets are designed to hold the bulb against a tensioned connection).

• If the PS isn't providing proper current or there's resistance at the connections, you'll see a voltage drop across the filament, thus yielding a warmer color temp.

• Also, over time, the bottom contact on the bulb, which is a soft metal, can significantly deform due to heat, lessoning pressure against the contact.

• The contacts can also oxidize. On my cars that have these types of bulbs, I clean the contacts when I happen to have the signal lens off.

• And the connection for the bottom of the bulb can slacken. With a small needle nose plier or curved pick, I gently pull the spring-steel contact for that presses against the bottom of the bulb out a little bit, to keep the connection snug.

• If a bulb is functional but the contact has deformed a lot, I'll replace it even if it still works.

In short, check to see if the bulb contacts have deformed or oxidized, be sure the bottom connectors exert sufficient force against the bulbs, and test the output of the power supply.

 

[eldon]

Thank you for your response. The copy stand I am using is ancient. The bulbs that came with it just say GE93 3200 Kelvin. They actually might be 50 or 60 years old. The unit plugs into 110 volt wall current and I think the voltage steps down to about 12V . After doing a rough test with my voltage tester I think the sockets are AC, But this is way above ,my expertise. Ideally I would like to get new bulbs with consistent color temp. From my research, LED's might work. I found one LED bulb that said 12V AC/DC, but most say just DC and would most likely melt or blow up if I have AC current at the sockets. also the owners manual says the bulbs are high intensity, low current. I will definitely look over your suggestions in detail. Thanks again for the thorough response. This site is a great resource.

 

[eldon]

I went back and read your answer again after posting.. I need to get it out of my head that the answer is a 12V AC bayonet bulb. I will look into all your suggestions.Thanks again.

 

[Ellis Vener]

You’ll probably have to simply replace the existing lighting fixtures and by pass the original power supply.

Ro me that seems to be easiest and more reliable road to take.

 

[eldon]

I was hoping to avoid that. Thank you for your honesty. The mechanical adjustments are really well designed on this old copy stand. It would be worth updating the lights. Thanks for your input. Should I click on mark as answered any time a

reply has valuable information even if the question is not a definitive answer. Want to give credit when I can.

 

[Ellis Vener]

If I post a response or a question which is helpful, yes do mark it.