hp 28s yellowed keys.

[Rafa]

(05-30-2024 05:30 PM)Maximilian Hohmann Wrote:  Hello!

(05-30-2024 06:39 AM)Rafa Wrote:  Is there a safe way to brighten up the keys and restore them to their original tint without having to dismantle the calculator?

Maybe with ozone, but who knows what this will do with the rest of your calculator. From your picture (taken with a phone?) it is not really obviuos to me what wrong colours you see in your calculator. The purple shift key looks perfectly normal to me, the bright red ones shown in some photographs are not what the calculator really looks like!

Right now I only have an HP-28C on my desk for comparison, but its white keys are not really white either, rather something between beige and light grey. I will attach a photo of that calculator below that I took on a white sheet of paper for white-balancing in a graphics program.

Regards
Max

Hi max,

thanks for answering. i did take the photo with a phone and made few attempts to capture the colours as the are but the results were always way brighter, which made me think that possibly all these other hp 28s in photos or in youtube videos are also being brighten up by the lens? the photo i uploaded was taken in a darker room and the result was still brighter than the real colours!

i'm aware that the numerical keys are actually cream rather than white and the shift key is kind of dark red, but the reason i'm suspecting mine is unusually dark is that the cream keys have a clear yellowish tint to them and the shift key is crimson red, which is not that bad. it is the yellowish keys that give me an eye sore. i definitely am not so bothered that i'd try some risky chemical sorcery. I thought that if this was an easy rub with something that one can buy in Rossmann and does not seep into the electronics then i might consider it.
I guess if you did manage to capture the real colours of your 28c then from what i see mine is definitely duller and darker.

i think i will just have to see another device to compare it side by side with mine.

many thanks again for the reply and the photo!