PBT key caps in general are less prone to yellowing than ABS plastic. Because KBT Pure comes out in only black or charcoal gray like colour such yellowing will not be easily seen on ABS based key caps.
Yellowing would take quite a while to be visible, and as you said since the caps are black that is not an issue at all.
Yeah though shiny factor still remains. Even if the key cap is made of dark paint which is furthermore resistant to yellowing for instance it still isn't going to be completely resistant to shiny factor.
The shiny factor with ABS plastic maybe the intermediate results of what will later on become yellow for ABS plastic however that is not noted on the deskthority wiki but of a more personal note.
Shine should not be related to yellowing, old plastic is usually yellowed evenly and not primarily on areas which get touched more often (i.e. old keyboards have yellowed cases and caps).
I actually thought the shiny factor might also be related to the fact that one maybe using keyboards with oily hands. There could be a few possible causes of this such as:
- One is eating food with bare hands and then later on smearing them onto key caps as they type. For example eating pizza in front of computer and then chatting away by typing on the keyboard.
- Naturally oily/greasy hands which often leaves marks on places (usually porous surfaces are the most susceptible I believe).
I don't know much about yellowing, have thought that the yellowing factor could be a combination of one's greasy/oily hands combined with exposure to natural environments such as sun, dust, etc leads to yellowing. However you mentioned that it should be evenly spread across the keyboard and the keys so it might indeed not be the result of environmental exposure.
Then again, another question comes to mind, according to deskthority wiki yellowing is a gradual process when such plastic is subjected to ultraviolet light or sunlight:
ABS (and other polystyrene blends) will gradually turn yellow over time when subjected to ultraviolet light, a component of sunlight.
If say theoretically a ABS based keyboard is being placed under direct exposure for extended periods of time but because of the exact area in which the keyboard is placed in under the exposure of sunlight is very narrow (such as on a certain area near the narrow window sill but the window sill is partly covered by some other material which usually blocks UV lights). Wouldn't only the exposed keyboard area (that has been mostly exposed to sunlight constantly at various angles of the day) be yellowed as opposed to having the entire keyboard being equally yellowed? I mean even if the other parts of the keyboard that are not exposed to the sunlight at all would also gets treated the same way regardless? What about also on the back of the keyboard considering most people do not leave their keyboards laying upside down in front of a computer whilst connected?
A bit of a comment on PBT based key caps is that they are mostly found on Topre branded boards.
Not really true. Quite a few keyboards come with PBT caps: Poker 2, Pure, Pure Pro, some Duckys, some Keycool boards...
Thanks, I don't know much from the Cherry MX range but have seen at times certain Cherry MX boards are using ABS plastic or even those aftermarket key caps seems to be offered at times as ABS as opposed to PBT.
Maybe I should have pointed that out earlier as I do now recall that some Ducky did have PBT key caps in their range. Although rare (limited production or otherwise) it is not the standard.
Also I was intending to say that the PBT key caps is being used right throughout the range. For instance all PFU HHKB Pro are PBT based, you don't have ABS mixed within the same "family", the same goes with Realforce keyboards with all keyboards are PBT and no ABS.
Ducky for instance or Poker II is offered in both ABS or PBT however ABS range is more diverse than PBT.
Therefore it maybe seen as PBT key caps aren't as cheap and as common as ABS based keycap.
PBT is less prune to developing shine and is afaik a more expensive plastic. However ABS vs. PBT is a question of preference.
Definitely I can agree that PBT is less vulnerable to shining/yellowing, also that is usually seen as more expensive grade/type of plastic.
On the subject of personal preferences, I can partly agree with. In most cases that is true at the end of the day regardless of whichever one chooses, PBT, ABS, POM, PVC, etc however between ABS and PBT alone PBT seems slightly more beneficial. Possibly as a more logical point of view PBT is really beneficial mainly in terms of where shiny/yellowing factor is of one's concern.
Inevitably PBT may not be entirely more superior to ABS apart from a few specific factors (due to the type of chemical/material used is completely different needless to say) PBT is often somewhat well regarded as those seeking for better quality. Granted also that PBT is not completely immune to shine as that will eventually happen but on a much slower rate than say ABS.
