Is it an issue if the white and black keys are weighted differently?

Question

I am looking to upgrade my keyboard from one with unweighted (springy) keys to one with weighted keys that feels more like a real piano.

I'd like to buy the new CASIO PX-S1100. When I look at a lot of reviews of the keyboard there seems to be some contention over the black keys being lighter than the white keys. When I played the PX-S1000 in the store I could not tell the difference between the white and black keys but that is probably because I am a beginner and the difference may become more noticible as I get more experienced.

I am looking for some clarity on piano key weighting.

What causes the "weight" of a key in a real piano?

Is there a weight range that piano manufacturers aim to be in with their key weighting?

I understand that keys get lighter as you move to the higher keys. Why is that? Is that consistent across every piano?

Wouldn't every piano manufacturer aim to have the black keys lighter because the length of the key is shorter so it is a shorter lever that might "feel" heavier?

If I spend a lot of time practicing with the PX-S1100, when I play on a real piano will having equally weighted keys feel weird?

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EDIT - Here are some of the reviews from different perspectives that I have watched regarding the PX-S1100:

Merriam Music mentions the weighting issue at 10 minutes & talks about it for the rest of the video.

Pretty much the entire ThePianoforever video is about the key weighting issue.

PianoManChuck didn't consider key weights important enough to mention is his video at all.

Answer 1

On a typical piano or organ keyboard, the fulcrum of each key lever is located significantly behind the back of the keyboard. As a consequence, while pushing the back of the exposed part of each key will require more force than pushing the front, the difference won't be particularly huge.

The complaint in the PianoForever video is primarily that a keyboard which is designed to be as compact as possible won't be able to place the fulcrum as far back as it would be on a more conventional keyboard. This greatly increases the amount by which the amount of force needed to actuate each key will vary with distance from the fulcrum.

If a compact keyboard were deisgned to use equal springs on the white and black keys, it would feel uneven because the back keys aren't as long as the white keys. Casio designed their mechanism to try to compensate for this, but the amount of compensation required would vary depending upon whether someone plays nearer the tips of the keys or nearer the backs. It sounds as though Casio may have over-compensated for key lengths, but what ratio of white key and back key strength would be optimal would be different for different performers.

Answer 2

TL;DR: It's a matter of personal taste.

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Preface: I've played scores of different pianos and keyboards, and it has never once dawned on me that the black and white keys were weighted differently.

A semi-scientific test: I measured the key weights of C4 (middle C), C#4, C6 (two octaves above middle C), and C#6 on two different (acoustic) pianos. I used stacks of nickels¹ placed at the leading edge of each key and looked to see how many were required to depress and hold the key past its escapement.

Results (in # of nickels):

Piano	C4	C#4	C6	C#6
Baldwin 6'3" grand	19	18	18	16
Yamaha 45" vertical	20	21	16	18

Observations: The black keys are lighter than the white on the Baldwin, but heavier on the Yamaha. However, I've played both pianos for 10 years or more, am perfectly happy with both, and can play the same music comfortably on both.²

Conclusion: Key weight, and differences in key weight between white and black keys, vary from instrument to instrument (and technician to technician, presumably), and are a matter of personal preference or indifference.

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Notes:

¹ According to the U.S. Mint Coin Specifications, a nickel weighs 5 grams.

² Although I've never noticed the key weights to matter, the action itself does. Pieces with rapidly repeated notes are much easier to play on the grand.

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See also:

I stumbled onto the following discussion, in which someone performed a similar test.

Answer 3

When I play music at the time with the black keys, I move my hand deeper on the keyboard, playing both black keys and the white keys at about the same length. I feel both black keys and white keys are heavier then white keys when I play them outside, near the edge of the keyboard. It makes sense.

When I teach my children piano, they complain that the black keys are more difficult to play. I told them to move their hand deeper on the keyboard, so that they need not to spread out their fingers more to strike the black keys, and spread their finger less to play the white keys. They did say that the keys become heavier when they play with their hand deeper on the keyboard. Later on, they accept the fact, and get use to it.