I display my very modest collection of HP's in a glass front cabinet above my computer monitor. Should I be worried about the keyboard markings fading over time. Direct sunlight never hits them, but sunlight does filter into the room. Does anybody have any experience with this?

Thanks and best regards, Hal

Could be a possibility. I find some of my calculators have the paint on the keys faint (not my HPs, of course). But I find it due to the calcualtor being in the pocket or being rubbed against the backpack.

I just dragged out my 30+ year old HP35, and the keyboard looks just fine to me. During its youth, this calculator was left on my desktop all the time, exposed to whatever light was around. It has spent most of the last 15 years or so in a desk drawer, however. My HP11C and HP41CV which I have owned since they were new (and early in the life cycle of these products) also look pretty good to me, and they've not been babied with respect to light exposure.

The usual culprit for fading is ultraviolet light (UV), the photons of which have the highest energy and are most likely to interact with the pigments. Even a simple pane of glass absorbs most UV radiation. I suspect your keyboards behind glass are OK.

In my active times as a student (>25 years ago) calculators were sitting everywhere. Also in direct sunlight behind big windows on our desks in the summertime, if we forgot to pull down the shade while we were working in another room. I do not remember any effect on the keys nor do I see any in the calcs I collected (and I have a 97 on my desk at home in direct sunlight since 2000).

As you will never get a tan behind a window, your calcs will not suffer there. Enjoy!

Remark: The white *housings* of Woodstocks and Topcats may turn yellowish - that's the only change I observed. No idea whether that's caused by light or oxidation.

Best place for your HP calculator is on your desk...

Mike T.

the keyboard won't fade - at least I have never seen a yellowed or bleached out one; there do exist some models with overprinted keys (limited only to the 10C?), which might wear...
the cases of the 21-27 and 97 will certainly yellow over time and should not be placed in direct sunlight; usual office light shouldn't be a huge problem though

I've noticed on a few of my calc's that the yellow legends above the keys has faded to a kind of tan color, whereas on several other calc's, they remain a bright yellow. Exposure to certain knds of light might be a factor.

-- KS

Edited: 4 Mar 2006, 4:04 p.m.