Problem Glass fogging

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Brad Jaeck

Grumbler in Training
Joined
Jul 15, 2020
Posts
6
Loc
Racine WI
Business
Photographic Design Gallery & Frami
We print our own photos on an epson printer and then let them dry for a day or two, We then mat and frame them using UV glass, then we exhibit them at outside art fairs. After a few hours the inside of the glass fogs up. Looking for ideas on how to stop the fogging. My concern is if they for up for us they may also fog up for our customers.
 
As soon as you wrote 'outside'.... that is probably where the problem is. How humid is the outside? What temperature changes does the whole package go through? Heating/ a/c then outside.

A better option would probably be to go with UV plexi glass but I am not sure if that will eliminate the problem completely.

I will also move this post to the first forum.
 
Do they unfog when you put them back into your car and then bring them back home?
 
If there is any moisture in the matt or any part of the framing package and you expose it to sunlight, even mild sunlight, outside the moisture will evaporate and fog the glass. The only way to avoid this would be to "cook" your matt in a warm vacuum press or other mild heat source to ensure it is thoroughly dry before closing up the package.
 
Hi, Brad. Using acrylic would likely lessen the fogging. It does scratch easily, but it has less of the moisture-forming reaction of glass. You might try just switching one out and seeing how it responds.
 
I also used to sell my photos at outdoor craft fairs and markets.
I see this all the time at local craft fairs in my region (also high humidity) where photographers and artists are selling framed prints.

Keep in mind that the "fogging" is moisture that is not disappearing when you no longer see it.
That is air inside the package reacting to humidity/temperature differences, and it is moisture that will be absorbed by the matting and could damage the photos if it happens too often.

This "fogging" has nothing to do with the frames themselves, it has to do with the environment they are in....the outdoors.
This is clear when your framed items are in reasonably controlled indoor environment. They aren't "fogging" there are they?

When your customer takes a frame home, it will acclimatize to the new home environment and not have this "fogging" issue.
(Unless where it is located in the home is susceptible to high humidity or temperature changes as well, but that is beyond your control.)
You can only control the outdoor environment at a fair/market a very tiny amount.
The sun is not your friend in outdoor displays, that is for sure.

How is your display space set up?
What kind of racking, tables or shelfs do you use?
Do you use a "standard" 10'x10' market tent? You can buy or make canvas or fabric walls to add more shade on one or more sides of the tent.

Take a look at other sellers and see who is having the same problem as you, and who is not.
Make note of how the "non-foggers" have their displays set up.

I noticed that the cleverer folks had displays that blocked or shaded the sun as much as possible.
One lady had nice frilly/lacey curtains in front of her tent to minimize the sun and made her tent very inviting to visit.
Another had made her display panels out of thin 1/8" plywood. The framed prints were hung on the shaded side only, the signage and non-framed samples were on the outside to draw attention.
Is your fair/market setup on green grass? Don't leave any frames down on the grass. So much moisture there!

What type of frames are you using?
Solid wood? Aluminum channel? Back loading "gallery" frames?

Also, are your frames sealed at the back?
Do a test with two identical framed pieces.
Cover the back of one and leave the other open.
See if there is any difference in the amount of fogging.
If the sealed one fogs less, that is a clue.
Changing from a simple paper sealed back to a better moisture barrier such as Tyvek could help. But that will come at a higher cost.

As others have mentioned acrylic could be better than glass in this situation for a couple of reasons. Again, at a higher cost.

From my personal experience, the simplest thing was to avoid the sun as much as possible.
 
Q? Are you using glossy or luster paper? These papers cause more fogging that mat paper.
 
As noted by others above, dew point is the issue here. If you look up a dew point chart online, you will see that moisture condenses on a surface under these conditions:
1. When humidity is present; more humidity = more condensation
2. When surface temperature is cooler than air temperature by a specific differential.

The dew point condition can develop quickly, and then go away quickly, as the temperatures of the air and the surface equalize and the differential diminishes. However, the resulting condensation may be visible for some time, as evaporation slowly takes place.

The air/surface temperature differential necessary to condense moisture varies according to temperature and humidity, which is clearly shown in a dew point chart. In typical ambient conditions of 70 F degrees and 50% RH, the air/surface temperature differential needs to be about 20 F degrees. But at 75% RH, the differential needs to be only 9 degrees, and at 85% RH, moisture condenses with a temperature differential of just 5 degrees.

Dew point condensation is the main reason why glass should never be placed in direct contact with items framed (abrasion is another reason). Glass is a poor insulator and transmits heat quickly, so when a frame is exposed to rapid, radical temperature change, dew point can occur easily. Acrylic is a better insulator and transmits heat more slowly, so the dew point usually will not occur. However, it still can occur if the change is rapid and radical enough.

There is no mystery to the dew point condition. To avoid the moisture in your frames, here are a few suggestions:
1. Avoid direct sunlight, because it radiates a lot of heat.

2. Keep your frames wrapped in insulating materials (blankets, paper, cardboard boxes, etc.) during transit and allow them to adapt to new ambient conditions slowly enough to avoid the temperature differential needed for the dew point.

3. Use acrylic instead of glass.

(Shameless plug: The DCO book includes a detailed description and illustrations explaining dew point, starting on page 41.)
 
Last edited:
Brad Jaeck said:
We print our own photos on an epson printer and then let them dry for a day or two, We then mat and frame them using UV glass, then we exhibit them at outside art fairs. After a few hours the inside of the glass fogs up. Looking for ideas on how to stop the fogging. My concern is if they for up for us they may also fog up for our customers.
Click to expand...
There is a good chance that part of what you are seeing is outgassing from the print drying. The longer you can print them before you frame them the better. It is even better if you can keep them in a low humidity room for a few days. We are a print shop that runs Epson printers and I have to be real careful with this more so on photo papers then art papers. I agree with the others above that you are getting some humidity issues also and acrylic would help. But definitely let them air out as long as possible before framing.
Eric
 
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