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I want to create a color that has the following properties:
red: 1
green: .478431
blue: 1
alpha: 1
How do I do that in the Photoshop CC 2018?
This all seems unnecessarily complicated. The common way we see RGB colour values from 0 to 255 is wrong by every colour science. Colour values are actually in the range 0 to about 1. It so happens that in an 8 bit image that pixel values are in the range 0 to 255 And it’s become a common but wrong way to talk about colour values.
It’s rather bizarre that in the same breath we talk about CMYK values as being in the range 0 to 100, since they are also actually in the range 0.0 to 1.0, and stored
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Where did you get those values from? They don't add up to a color. Red, Green and Blue colors can only be from 0-255. Alpha is not a color.
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green: .478431???
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Not possible. The Color Picker, no matter what color model, deals in whole numbers like 1, not fractions such as .478431.
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If you are dealing with a range from zero to one, you could normalize that to 0 - 255, and Green would give you a value of 122:
The Alpha value could be the opacity of a layer, or a layer mask, or a saved selection, or any number of things.
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The only color system I am aware of that deals in decimals with a range of 0 to 1 is Xyz
Using http://colormine.org/convert/xyz-to-lab
I came up with a conversion to Lab
Those values in the Color Picker will do the RGB conversion.
Assuming Adobe RGB: R16 G31 B10. It is a type of black
According to the Lab readout it is black with a very slight green cast.
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What are you planning to use the color for? Is it a screen value, or print? And where did you get those values?
If you can answer these, it would help us to give you a more effective answer.
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The float colors values (.478431) are achievable only in 32bit color Bit depth, you need to change the current document to use 32bit colour channel, you can do so by going to Menu > Image > Mode > 32 bit channel than open color picker to enter the RGB values, and alpha is extra channel added in a RGB color document, if you working with transparency(I.E. Masking ).
Screenshots for reference -
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This all seems unnecessarily complicated. The common way we see RGB colour values from 0 to 255 is wrong by every colour science. Colour values are actually in the range 0 to about 1. It so happens that in an 8 bit image that pixel values are in the range 0 to 255 And it’s become a common but wrong way to talk about colour values.
It’s rather bizarre that in the same breath we talk about CMYK values as being in the range 0 to 100, since they are also actually in the range 0.0 to 1.0, and stored in an 8 not image as 0 to 255.
Anyway if you have correct colour values in the range 0 to 1, but have to use a colour picker in the range 0 to 255, just multiply your colour values by 255.0. Job done, no need to convert to 32 bit, imagine they must be XYZ (no!) or do anything else.
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Ok. That makes sense. Thank you. As you see in the image below I have converted 0.478431 to 122 in order to conform to the range of 0 to 255.
What about the alpha value of 1? Doesn't that mean I don't need to do anything else in the color picker? Isn't the alpha automatically a value of 1?
@
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as Semaphoric said: "The Alpha value could be the opacity of a layer, or a layer mask, or a saved selection, or any number of things."
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Alpha in photoshop isn’t a colour property. It’s (always) an amount of transparency but in Photoshop you do this with transparency effects. The good news is that alpha = 1.0 means fully opaque, just normal. So you ignore it.