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Author Topic: The Digital Negative - Blend If  (Read 1700 times)

Oldfox

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The Digital Negative - Blend If
« on: August 16, 2013, 09:38:46 am »

In the book "The Digital Negative" by Jeff Schewe, page 209, figure 5.7 the 'Blend If' part the two sliders are split. The values are 0 / 50 and 200 /255.

The text in the next page is "the sharpening will be fully applied between level 50 (on the left) and level 200 (on the right)" and "This tells Photoshop to roll off blending between level 50 and 0 and between level 200 and 255."

Maybe I have got it wrong but isn't the opposite happening? Levels 0-50 and 200-255 will be sharpened.

Or maybe I have missed something?
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Schewe

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Re: The Digital Negative - Blend If
« Reply #1 on: August 16, 2013, 02:08:54 pm »

In the book "The Digital Negative" by Jeff Schewe, page 209, figure 5.7 the 'Blend If' part the two sliders are split. The values are 0 / 50 and 200 /255.

The text in the next page is "the sharpening will be fully applied between level 50 (on the left) and level 200 (on the right)" and "This tells Photoshop to roll off blending between level 50 and 0 and between level 200 and 255."

Maybe I have got it wrong but isn't the opposite happening? Levels 0-50 and 200-255 will be sharpened.

Or maybe I have missed something?

What I wrote is correct...the blend of the top layer to the bottom layer happens between level 50 & 200, it rolls off (decreases) between 50-0 and 200-255.
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JimGoshorn

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Re: The Digital Negative - Blend If
« Reply #2 on: August 16, 2013, 02:11:31 pm »

When you set the blend-if sliders at 0-50 and 200-255, what is happening is that at 0 you get no application of the sharpening and it gradually builds up to 100% application at 50. It stays at 100% till you reach 200 and then fades out to 0 at 255. If you were to set the sliders at 80/100 and 180/200 for example, then you would have no application from 0 to 80 and 100% application by 100 until 180 where it fades back to no application by 200 and beyond.

Does that explanation make sense?

Jim
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Oldfox

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Re: The Digital Negative - Blend If
« Reply #3 on: August 17, 2013, 02:03:03 am »

Thanks for the answers. Jim's explanations is very good. English is not my first language, I did not understand 'roll off'.

I experimented the blending with my own image (there was no sample image: "MORE IMAGES TO COME! (check back soon)"  ;) ) and made the wrong conclusion. Thanks for the explanation!

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stamper

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Re: The Digital Negative - Blend If
« Reply #4 on: August 17, 2013, 03:55:16 am »

'roll off' means fading or tapering or feathering. The blend if is a little known technique that deserves more attention and should be - imo - incorporated into everybody's workflow. There are quite a few ways it can be used and till recently there wasn't much information about it in print. A couple of my PS books don't even mention it let alone explain it's many uses.
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