• Alfred
  • Alfred
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Re: Modalities of producing an electronic Art Show

William wrote:

Do you know how each of the red, green, and blue channels is calculated when opacity of a layer is used please?

I am wondering if it is, if opacity is expressed as a value p in the range 0.0 to 1.0, if there are n layers, as

x = p * x(i) + (1 - p) * x(i - 1)

Alas, I cannot use square brackets, as the forum software treats them as markup.

…

Using Paint to look at what is the colour gives (153, 153, 204), so it looks like my guess at the formula might be correct, at least for just one semi-opaque layer upon an opaque layer.

I think your formula is indeed correct, unless we’re both missing something!


As for using square brackets, you need to ‘escape’ them by using {code} markup via the ‘angle brackets’ button on the toolbar above the message text area.

x = p * x[i] + (1 - p) * x[i - 1]
"Has it ever struck you that life is all memory, except for the one present moment that goes by you so quick you hardly catch it going?"
― Tennessee Williams
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Re: Modalities of producing an electronic Art Show

The blue background has (r, g, b) values as follows.

(128, 128, 255)

The five colours of the bands have (r, g, b) values as follows.

(153, 153, 204)

(173, 173, 163)

(189, 189, 130)

(202, 202, 104)

(213, 213, 83)


heading towards (255, 255, 0)

So it seems that the colours move from the background colour towards the yellow colour of the bands as a sort of chunky exponential decay.

William

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Re: Modalities of producing an electronic Art Show

https://i.postimg.cc/MMzvPmkt/sunlight3.png

  • Alfred
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Re: Modalities of producing an electronic Art Show

William wrote:

So it seems that the colours move from the background colour towards the yellow colour of the bands as a sort of chunky exponential decay.

You can change the shape of the decay curve by altering the parameters of the gradient.

"Has it ever struck you that life is all memory, except for the one present moment that goes by you so quick you hardly catch it going?"
― Tennessee Williams
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Re: Modalities of producing an electronic Art Show

Alfred wrote:

You can change the shape of the decay curve by altering the parameters of the gradient.

Is that by changing the opacity from the 20% that I used?

Or something else?

William

  • Alfred
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Re: Modalities of producing an electronic Art Show

William wrote:
Alfred wrote:

You can change the shape of the decay curve by altering the parameters of the gradient.

Is that by changing the opacity from the 20% that I used?

Or something else?

William

You can alter the other parameters, too. When you choose the Fill Tool, the control line has stops for the different colours and opacities along the gradient. You can add or remove stops, and you can reposition the stops or the ‘midpoints’ between pairs of stops (positioned exactly halfway by default).

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"Has it ever struck you that life is all memory, except for the one present moment that goes by you so quick you hardly catch it going?"
― Tennessee Williams