Paul Dempsey wrote:
sounds to me like you're taking the "art" out of photography and turning it into a math equation....ther'e s abook you should check out ..."Drawing on the Right Side of the Brain"  It's designed to help people get away from the over analytical thinking and rely more on the creative side (the right side ) of your brain...plus, it's just way more fun to look at photography as an art form rather than a math problem.

ronald n. tan wrote:
Edit: I see nothing wrong with appreciating the beauty of science/mathematics behind image processing. Your post is insulting to the sharing generosity of Sean; I for one do not appreciate.

ronald n. tan
www.ronaldntan.com

i'll second that...  an take it one further that the processing of an image IS in fact an art.  Having a more technical approach to said art does not in fact invalidate it as an art, merely changes the design and process of said art.

Modstudios wrote:
Can we see an example?

Sure.  The image below is the difference between a HP + GB solution for frequency separation and the original image.  Processing was done in 16bit mode with a 5px radius when the image was 800x527.  Resized to save reading space, but no other modifications were made.



The same difference image is pure black when separated using the above technique.  I can post it if you like, but it really is all black in 8bit (JPG).

Let me know if that's what you were hoping to see.

Sean

Paul Dempsey wrote:
sounds to me like you're taking the "art" out of photography and turning it into a math equation....ther'e s abook you should check out ..."Drawing on the Right Side of the Brain"  It's designed to help people get away from the over analytical thinking and rely more on the creative side (the right side ) of your brain...plus, it's just way more fun to look at photography as an art form rather than a math problem.

Is it your assumption that a person needs to be a stupid dolt in order to appreciate art, or do you feel the opposite, that smart people can't appreciate art.

Jarrad Kevin wrote:
Example 100% crop

I felt the new technique needed around 35% more to match the amount of sharpening down by high pass on soft light blend mode.

Great composite for demonstration.  Out of curiosity, how're you exceeding 100% for the blend mode?  Duplicate layer?

And FWIW, I'm not trying to assert this as being a fantastic sharpening technique.  My currently preferred sharpening is here.  Sharpening is simply one thing you can do with this technique and my intent here is just to share a better way of performing frequency-based seps.

Sean Baker wrote:
Out of curiosity, how're you exceeding 100% for the blend mode?  Duplicate layer?

Yes, one layer at 100% and another at 35%.

Thanks for sharing the technique.

Robert Randall wrote:
Sean helped me work through the process earlier today, and I came up with a varient on full sized files. I have never seen sharpness like I achieved today, and I've been doing this for 20 years.

Just wait till you apply a clipping-masked curves layer to that high-frequency layer .

Photo Visions wrote:
I am not going to read all that.

I look to create an image i can enjoy.

You take the joy out of photography.

wha...?

Photo Visions wrote:
I am not going to read all that.

I look to create an image i can enjoy.

You take the joy out of photography.

Are you kidding?  Why even post in the thread then... just move on and spare us.  You take the joy out of reading helpful posts in a forum that is generally filled with crap like your post.

Sean, thanks for sharing your experience and knowledge, I'm not at my home computer now but sounds very interesting.

Photo Visions wrote:
I am not going to read all that.

I look to create an image i can enjoy.

You take the joy out of photography.

After looking at both of your portfolios, I've made up my mind which post to take seriously.

Paul Dempsey wrote:
sounds to me like you're taking the "art" out of photography and turning it into a math equation....ther'e s abook you should check out ..."Drawing on the Right Side of the Brain"  It's designed to help people get away from the over analytical thinking and rely more on the creative side (the right side ) of your brain...plus, it's just way more fun to look at photography as an art form rather than a math problem.

No, he's giving the artist yet another tool to control his/her creations and to understand the medium in which he/she works.  How can you so casually dismiss knowledge like this?  I don't understand that.

-=>Donald

Paul Dempsey wrote:
sounds to me like you're taking the "art" out of photography and turning it into a math equation....ther'e s abook you should check out ..."Drawing on the Right Side of the Brain"  It's designed to help people get away from the over analytical thinking and rely more on the creative side (the right side ) of your brain...plus, it's just way more fun to look at photography as an art form rather than a math problem.

Those darn scientists! Dabbling in the black arts of photon measurements, Bayer demosaicking, image reconstruction, and all the ills of digital! We should go back to the days when photographers didn't need to worry about optical properties and light, chemistry, emulsion coatings, and thin-film behavior, and any of those other over-analytical processes...

...which are the underpinnings of the craft on which the art is based.

SIFTHI

Sean, thank you.

Photo Visions wrote:
I am not going to read all that.

I look to create an image i can enjoy.

You take the joy out of photography.

No worries. Many photographers base their career on Holga-esque images. For those photographers, no understanding of sharpness, acuity, or related issues is necessary.

Many photographers also fail to understand that clear misunderstandings of the underpinnings of the craft they engage in can have repercussions far beyond the embarrassment of claiming sRGB and Adobe RGB have substantially different numbers of colors.

Knowledge can be useful.

Sean, thank you again.

Paul Dempsey wrote:
sounds to me like you're taking the "art" out of photography and turning it into a math equation....ther'e s abook you should check out ..."Drawing on the Right Side of the Brain"  It's designed to help people get away from the over analytical thinking and rely more on the creative side (the right side ) of your brain...plus, it's just way more fun to look at photography as an art form rather than a math problem.

You mean I spent all those years in a darkroom making certain the D-76, Acufine, and Rodinal were at the precise temperature, making certain the development times were spot on, the agitation just so, the dryer at the correct temperature all for nothing?  I was messing with the art- huh? - by practicing precision and by testing my Tri-X in various chemistries until I found which worked best when I needed to pull or push my film speed.

What about the print process?  Paper choices; tone and amount of silver, developer; secret brew or Dektol? toning chemicals? times? blah blah blah -- not artistic concerns cause they deal with chemistry and math?

And what about all that f-stop, shutter speed, iso, dof, lens angle, blah blah blah -- not artistic cause it involves math?

I presume you use a computer in your camera and on your desktop to acquire and make your images publishable on this site. Yes?  That's all math baby.  Nothing but 1s and zeros dancing to the programmers music.

Tim Hammond wrote:
Going through the 16 bit method, I get to the second step 6 and I have no place to enter scale and offset.  Can someone point out what I'm missing?

Under blending, further down theres "Add" and "Subtract" not what you have selected (linear dodge add).

Sean Baker wrote:
Findings / Technique: In my own experimentation, I've found that HP gives differences as high as 2670/32k per pixel when separating high and low frequency information.  The proposed alternative technique for working with 8bit image data is as follows:

  1.) Start with two copies of the image to be separated.
  2.) Working on the bottom copy, run the gaussian blur filter at the intended pixel frequency (same as you would input into the HP filter).
  3.) Selecting the top copy, choose Apply Image from the Image menu at top (Shift+Ctrl+A on PC; Cmd+Shift+A for Mac).
  4.) In the Layer dialog, select the bottom layer which you blurred in step 2.
  5.) In the Blending dialog, choose Subtract.
  6.) Enter '2' into the Scale box, and '128' for the Offset.
  7.) Preserve Transparency, Mask, and Invert should not be checked.
  8.) Choose OK.
  9.) Your top layer will now look much as a HP result, albeit a bit flatter.  Set the Blend Mode to Linear Light.  Opacity should remain at 100%.

Working in 8bit mode, this will give you an accurate frequency separation to about 115/32k.

Just quickly trying it out:
So I understand the 128 offset is giving 50% gray, what is the scale affecting?

Also for the high pass method I typicallly used the channel mixer with one of the color filters to get my greyscale image. It gave different effects depending on the scene letting you control the contrast more. There any steps you can add to your method to do the same thing? I think your method gives an overall sharpening but at the same time makes it look flatter(?) i.e. less perception of depth in the overall image



I admit total ignorance at the "buncha numbers per pixel" thing you were talking about.

DarkSlide wrote:
Do I understand you correctly, this action is designed for a 800 px @ 72 dpi file size? I've tested it on several images that size it looks great.

The action is designed for any sized image and any separation radius which you care to use (at least, up to the limits of PS).  I just used one at 800px for the example due to MM size limits.  As Mr. Randall noted, he was able to use a derived technique on much larger files.

Sentimental Treasures wrote:
Don't know if I would say High Pass sucks... but I did like your post, and copied it to a file for more experimentation.  Keep up the good work in finding new solutions. I was able to appreciate the technical side after reading through it...  at first I was like WTF.

Never judge a post by it's intro    LOL

A bit of deliberate dramatic flair, I apologize.  I didn't want the information to be lost entirely with its technical nature.  That backfired a bit of course (scroll up ), but in the end at least a few can appreciate the utility of this.

Yingwah Productions wrote:
Under blending, further down theres "Add" and "Subtract" not what you have selected (linear dodge add).

This is exactly it.  Let us know if you're still having trouble (or use the action ).

Yingwah Productions wrote:
Just quickly trying it out:
So I understand the 128 offset is giving 50% gray, what is the scale affecting?

The scale is dividing the difference between the two images (the blurred copy and the original) by two.  We do this for two reasons - first, it allows us to use Linear Light for our blend mode at 100% which is convenient, and second because if you want to go back and put a clipped-curves layer on the high frequency detail it allows you more room to push the high and low luminance points.  If that doesn't make sense, don't worry, just try applying a curve to it and see what I'm talking about .

Yingwah Productions wrote:
Also for the high pass method I typicallly used the channel mixer with one of the color filters to get my greyscale image. It gave different effects depending on the scene letting you control the contrast more. There any steps you can add to your method to do the same thing? I think your method gives an overall sharpening but at the same time makes it look flatter(?) i.e. less perception of depth in the overall image

You can use your same way of starting this process.  Setup your channel mixer adjustment layer in your image.  Now select the uppermost visible layer and choose Stamp Visible to create a merged copy of the entire scene by pressing Shift+Ctrl+Alt+E (Cmd+Shift+Alt+E on Mac).  With the new layer selected, run the action as before.  You've now separated your created channel's spatial frequencies and can use either the high or low data to suit your needs, exactly as you did in the past, mind you a bit more accurately.  As Mr. Kevin notes, it will not be as dramatic out of the box as the old HP method if you use it for sharpening / local contrast - the advantage lies in having fewer artifacts.

Yingwah Productions wrote:
I admit total ignorance at the "buncha numbers per pixel" thing you were talking about.

Think about the example image I posted showing how different a HP + GB reconstruction of the image was from the original.  Clearly the image is largely dark, but with points which were markedly different.  Using threshold command and the eyedropper tool, I sought out the greatest points of difference between the original images and the separation results to determine the more accurate method, recording those levels of difference as a 16bit number.  I hope that helped clarify a bit.

And again to everyone offering support - thank you.  I've learned most of what I know from this forum and am relieved to be able to return something to all of you.  If anyone has lingering questions or suggestions for how this could be done better, please share them.  I'm serious in saying that I want to share what little I do know.

DMHolman wrote:

No, he's giving the artist yet another tool to control his/her creations and to understand the medium in which he/she works.  How can you so casually dismiss knowledge like this?  I don't understand that.


-=>Donald

When you've hung out in here long enough, you come to realize there are a large number of people that can't accomplish much in life. They need some form of reinforcement in their lives, and they seem to have chosen the art card for help with that. They can't make art, but they can hide behind the art card. Their arguments use the ploy of deflection to acheive credibility, much the same that OJ did during his murder trial. Everyone knows they are talentless hacks, but when they produce a snap shot of their girlfriend tugging at her soiled panties while sticking her ass out and giving the cell phone that come hither look that reminds you of a deer about to meet it's maker, they argue the picture is their art, and that somhow validates everything, and they are no longer a talentless hack screwing a toothless hag, they am be ARTEESTS!

Of course in this particular case, I'm sure the respondent is a highly talented artist that has a firm belief in the soul of his work. 

Or not.

Craig Thomson wrote:
Sean, I have no clue what your talking about with the layers and whatnot but I really do appreciate your humbling announcement to share your research with the masses. 

Kudos to you and others like you.

"You can only think outside the box when you know what the box is" Craig Thompson.

Robert Randall wrote:

When you've hung out in here long enough, you come to realize there are a large number of people that can't accomplish much in life. They need some form of reinforcement in their lives, and they seem to have chosen the art card for help with that. They can't make art, but they can hide behind the art card. Their arguments use the ploy of deflection to acheive credibility, much the same that OJ did during his murder trial. Everyone knows they are talentless hacks, but when they produce a snap shot of their girlfriend tugging at her soiled panties while sticking her ass out and giving the cell phone that come hither look that reminds you of a deer about to meet it's maker, they argue the picture is their art, and that somhow validates everything, and they are no longer a talentless hack screwing a toothless hag, they am be ARTEESTS!

Of course in this particular case, I'm sure the respondent is a highly talented artist that has a firm belief in the soul of his work. 

Or not.

Although you're obviously a talented photographer and are well respected as a brilliant technician, I think possibly your true calling is in writing posts like this one.

Figure out a way to turn that talent into money and you'll be very rich indeed.