Using "Blend If" for Selective Corrections.

[Flora]

Some practical usages for the Blend If Option in Photoshop. [details]

[Flora]

....Here I go again ....

.... Is it all there? .... images too????

Thanks ....

[Ed_L]

All the images are viewable!! Congratulations. While comparing the images when using selections and blend-if, it looks to me that the noise in the hair and the backs of the subjects in the background is a little better than the noise in the blend-if. But the sweater noise looks better in the blend-if image. Nevertheless, another great tutorial! Thanks for sharing your brain with us. I guess I'll have to try NeatImage after all.

Ed

[Flora]

Hi Ed,

Thank you very much for your kind feedback and words!

Originally Posted by Ed_L

While comparing the images when using selections and blend-if, it looks to me that the noise in the hair and the backs of the subjects in the background is a little better than the noise in the blend-if.

... It is always a matter of preferences ... and I actually left the 'Blend If' version a bit smoother on purpose ...
Fact is ... with the Blend if, I could have matched the other version exactly working simultaneously and yet separately on highlights and shadows in one go!

[JustChecking]

another powerful magic trick by flora!! thanks a lot for sharing

[Gary Richardson]

Thanks Flora (and Roger) for a great insight into the Blend If option. Not sure I got it all on first reading, but I'm definitely going to be having a play with this one.

[Flora]

JustChecking, Gary,

...Thank you so much for your great feedback!!

I'm actually thinking of changing it.... Once you get the hang of it, 'Blend If' is very, very versatile and quite easy to use ....

I've cut a few corners in my tutorial because Roger had already done such a complete and excellent job with his ... But I think I'll have to explain step by step, how, for instance, by simply using Blend If, you can make such a complex selection (see attachment), without any mask at all!

[kiska]

Oh, Flora ,PLEASE, a step by step.
kiska

[Flora]

Hi Kiska!

How are you?

... I'm preparing it ....

Very soon on these screens .... (if I get the images to upload ....)

[kiska]

I am breathlessly awaiting your next creation !
kiska

[gmitchel]

I'm glad I could help.

I use the Blend If sliders a lot in my work.

Cheers,

Mitch

[Flora]

Hi,

I've changed the tutorial ...

...hope everything is visible (and helpful! )

[JustChecking]

thanks for all the arrows and colour bars and ellipses etc.

had just little time to look at it (and saved the "printable" version), but the tut seems crystal clear, and super useable



thanks!

[kiska]

Flora,
I downloaded the 'goods'. Will play with it tomorrow. Thanks soooo much.
kiska

[Ed_L]

Flora,

Roger has a very nice tutorial for blend-if. I think yours compliments it admirably! The more I read about it, the more I play with it. Thanks for taking what must have been a long time writing this one. It's very good, and the screenshots are excellent!!

Ed

[roger_ele]

Thanks everyone for the nice comments

[Gary Richardson]

Flora, read the new edition of your tutorial, it's really one for my tool box, thanks for taking the time with this one. Ditto Roger for all your effort.

[Flora]

Hi everybody!

Thank you so much for your great comments and moral support!!!

... I do hope you'll find this technique a helpful 'shortcut' to some tedious work ... and sometimes even a quick solution for some more drastic procedure!

I'm still 'experimenting' with it ... curious to see how far I can get, particularly when used with adjustment Layers....

If you have any questions ... you all know where to find me

[Ed_L]

Originally Posted by Flora

Hi everybody!

If you have any questions ... you all know where to find me

How much time do you have?

Ed

[Flora]

[kiska]

It's rough, NOT my thing, but appropo.
kiska

[Flora]

WOW ... thanks Kiska!!!

...that's great!!!! ....

[Ed_L]

Now that says it all!

Ed

[hpycmpr]

Flora and Roger, Blend If is a topic all my $50 PS books won't touch with a ten foot pole. Thanks so much. You should seriously consider writing one yourselves. Suggested title: "PS Topics Not Found Elsewhere".

Flora, your tutorial seems to be a follow up on your Neat Image tutorial. Can you elaborate in more detail on how to apply Blend If to NI? An example will help. I assume that NI needs to be a plugin in this case?

[Flora]

Hi hpycmpr,

sorry for my delay in reacting ...

Originally Posted by hpycmpr

Flora and Roger, Blend If is a topic all my $50 PS books won't touch with a ten foot pole. Thanks so much. You should seriously consider writing one yourselves. Suggested title: "PS Topics Not Found Elsewhere".

Thank you so much for your kindness!!!

Originally Posted by hpycmpr

Flora, your tutorial seems to be a follow up on your Neat Image tutorial. Can you elaborate in more detail on how to apply Blend If to NI? An example will help.

... Originally it was ... but then I changed it to 'replacing a dull sky' .... as I thought it would be of a more practical usage ... but here is the example on using it with Neat Image ....

Attachment 1 is a cropped part of a picture taken from inside a boat ... the curtain came out nearly black when photographed against the bright light outside ...

Attachment 2 shows the curtain after I lifted the shadows in PS .... as you can see, the noise is very strong in the lightened parts, while there's practically no noise in the original lighter parts which were untouched by my 'lightening' procedure .... Before discovering what could be done with the 'Blend if' Option, I would have created a 'Shadow Mask' and denoised that only as described in the 'Using Neat Image with Selections' Tutorial .... If unhappy with the result, I would have had to repeat the whole 'denoising' procedure until I was satisfied ...

Attachment 3 shows what my picture looked like after duplicating the corrected-for-light Layer and running the duplicate through Neat Image (quite strong settings)... I was satisfied with the curtain, but the originally lighter parts of the picture had been blurred nearly beyond recognition .... That's when I used the Blend if Option ...

Attachment 4 shows the only changes I did with Blend if Option .... As you can see, I didn't change anything in the darker parts of the image since I wanted to keep the corrections done with Neat Image unchanged in those areas ... but I wanted to bring back some 'noise' and details in the originally lighter parts that's why I tweaked the right (light) sliders only.

Attachment 5 shows the end result ... The noise is balanced and I have all my details back in the originally lighter parts of my Image...

Originally Posted by hpycmpr

.... I assume that NI needs to be a plugin in this case?

No, it doesn't .... as long as you 'place/drag' the denoised layer/image on top of your corrected-for-light one ....

There might be pictures for which the Luminosity/Shadows Masks method works better .. but with 'Blend if' you have much more control on how much of the correction done you want to have in the different parts of your picture .... I could have just as well decreased the strenght of the denoising procedure on the curtain as well by simply tweaking the left (dark) sliders ...

using the power of Blend if, you can influence the strenght of your correction on the pixels from black to white in the channels individually (Blend If Red, Green or Blue etc. Options), or together (Blend If 'Gray' Option).

[hpycmpr]

I finally got around to trying your NI blend_if tutorial, and found it working wonderfully for me. Thank you so much. May I suggest adding this last example to your blend_if tutorial so that it can help other NI users as well.

I do have some additional questions (so what's new?). Can you clarify what the blend_if split sliders do? You mentioned that the width between them controls the "transition". Is that kind of like feathering a selection? Again, an example will be great.

I noticed that the blue channel of my film scans typically has the most noise. I often wonder would it make sense to only denoise the blue channel, or to denoise it aggressively first and then followed by another round of denoising the composite channels. This should work particularly well for images with a clear blue sky. Since NI does not work in rgb, I have not been able to try either approach. I have tried blend_if the r and g channels instead of gray to denoise only the b channel, and it seems to work. Are there better ways to do this?