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-   -   How to Sharpen (http://www.railpictures.net/forums/showthread.php?t=7081)

Peter MacCauley 04-07-2008 08:58 PM

How to Sharpen
 
I was just wondering what is the "correct" way to sharpen a photo. I gather that it should be the last step in the process, but i've seen some people who sharpen the photo a little bit before doing any editing, and then a little after editing. I myself use 75/0.6/0 for all my photos, unless one really needs a lot of sharpness. I guess it is also largely affected by equipment - some lenses are just better/sharper than others. Any hints/suggestions would be greatly appreciated.

Peter.

Railfan Ohio 04-07-2008 10:29 PM

The last thing I do before resizing is sharpen. It is usually around 100/1/0. Then I resize and sharpen again at 50/.5/0. This seems to work as I haven't had a sharpening related rejection for a long time.

chico 04-07-2008 10:42 PM

sharpening
 
I'm hardly the P/S expert here, but I would never sharpen until the final size has been rendered.

JRMDC 04-07-2008 11:27 PM

I do a bit of sharpening at the very beginning, at RAW conversion - a 25 setting in Adobe Camera Raw (part of PS and PS Elements). And then nothing until the very end, after resizing and everything else, when I do a 75/0.6/0. I have noticed with my 17-55 lens that I can cut it back to 75/0.4/0 - that is a sharp lens!

I have no particular reason for the initial sharpening - at some point it started working for me and I have chosen to leave it alone since. Don't change what works! :)

If I start with a jpg (scanned slide or digicam or "P" shot), then I do only the sharpening at the end.

travsirocz 04-08-2008 08:23 PM

Here is a technique I learned in a Scott Kelby book. When you sharpen, go to image, mode, lab color. Then on the right side under channels select lightness and sharpen just that channel. Once done go back to image, mode, srgb. This way you are not sharpining the color just the luminosity. His books also give many other sharpening tricks and techniques.

Ween 04-08-2008 08:27 PM

Quote:

Originally Posted by travsirocz
Here is a technique I learned in a Scott Kelby book. When you sharpen, go to image, mode, lab color. Then on the right side under channels select lightness and sharpen just that channel. Once done go back to image, mode, srgb. This way you are not sharpining the color just the luminosity. His books also give many other sharpening tricks and techniques.

That's what I've been using after Thomas Johnson pointed it out to me. By not sharpening the color, you avoid the color halos that can form from too much sharpening. So far, it seems to work well; I'll provide a link to a tutorial when I get home...

Ween 04-09-2008 06:28 AM

Here's the link:

http://www.dphotojournal.com/photosh...or-sharpening/

Kevin W-S 04-09-2008 06:59 AM

Ween - interesting. Thanks for this.

ijkl513 05-29-2008 06:19 AM

Question
 
hey, man. is there may i ask you a question about your topic?
here is my email : dmanbush@gmail.com
__________________________________________________ ______________________
Green Laser,Red Laser,Blue Laser,Qi Gong,Kung Fu,

Kevin W-S 05-29-2008 11:39 AM

I will contact you ,though you can ask the question here....

Walter S 05-29-2008 06:24 PM

Kevin I wouldnt e-mail this guy, he looks to be a spammer. I dont want you to get some virus or something.

Bill 05-30-2008 01:38 AM

This is a good tutorial as well...describes sharpening in simple terms.

http://photojojo.com/content/tutoria...hop-sharpening

Northern Limits 05-30-2008 03:14 AM

question?
 
Quote:

Originally Posted by Ween
That's what I've been using after Thomas Johnson pointed it out to me. By not sharpening the color, you avoid the color halos that can form from too much sharpening. So far, it seems to work well; I'll provide a link to a tutorial when I get home...

I have PS4, so no lab color mode.
So, if I go to Image> Convert Color Profile> Remove Profile — sharpen — then go back and > Apply sRGB Profile ... would that accomplish the same effect?

Ween 05-30-2008 03:34 AM

Quote:

Originally Posted by Northern Limits
I have PS4, so no lab color mode.
So, if I go to Image> Convert Color Profile> Remove Profile — sharpen — then go back and > Apply sRGB Profile ... would that accomplish the same effect?

I have no idea...

Kevin W-S 05-30-2008 06:24 AM

Thanks Walter! I actually just sent a PM which seemed the obvious thing to me - especially since he could have done the same. No reply.

Following the responses on sharpening I have been intrigued as to how generally the approaches seem to boil down to the same.

Ia have thought about it a lot more and now use DPP when doing the conversion from RAW and follow-up with PSPX -= good results mostly.

I open the photos up snd review them firstly with DPP - and excellent little program -

Select all, ALT q, MAXIMISE PICTURE. I then look through and mark the deletes - Alt 1. Delete them. Look through and mark the pics needing adjustment.

Adjust (and sharpen if required) with DPP.

Convert toi jpg.

Open with PSP. Crop. Resize. I then use generally only a sharpen tool to resharpen a fraction, then file SAVE AS, OPTIMIZER to resize the file size.

alan-crotty 05-30-2008 08:37 AM

Colour Profile Change
 
Hi Jim,


You asked:

So, if I go to Image> Convert Color Profile> Remove Profile — sharpen — then go back and > Apply sRGB Profile ... would that accomplish the same effect?


In a word no.

When you change the profile you're only altering the way colours are interpreted by other devices.

To achieve the sharpening technique described you have to be able to access LAB mode.

I can't remember back far enough to say if LAB was available in PS4.

Alan

John West 05-30-2008 06:28 PM

Scanned film versus digital originals
 
One thing that might be worth noting is there seems to be a big difference in the sharpening routine needed for scanned pictures and original digital images. I have been scanning slides for some years with good 4000 dpi scanners, and typically would need to sharpening them with something like 0/1.0/150 and then of course do an additional bit of sharpening after converting them from tiff to jpeg.

Now that I am shooting digital images I find my whole sharpening routine has changed....and I'm still trying to figure it out. But basically the images need a whole lot less sharpening. Which is probably something of a no brainer, but I thought the difference was worth mentioning in a discussion of sharpening.

In the beginning somebody convinced me that it was best to sharpen in small increments throughout the post processing. Now I have bought into the do it all at the end approach. I wonder if there is a definitive technical rationale for which is better.

Oversharpening seems to be one of the dangers of digital processing. I don't notice it so much on RP, because I think the screeners catch it. But at the digitally projected Winterail slide shows that I go to, I see a lot of images that appear to be oversharpened (or at least overprocessed). In general the digital processing produces equal or better images than projected film, but it also seems to take more experience to do it well.

Northern Limits 05-30-2008 09:22 PM

Quote:

Originally Posted by alan-crotty
Hi Jim,


You asked:
So, if I go to Image> Convert Color Profile> Remove Profile — sharpen — then go back and > Apply sRGB Profile ... would that accomplish the same effect?
In a word no.

When you change the profile you're only altering the way colours are interpreted by other devices.
To achieve the sharpening technique described you have to be able to access LAB mode.
I can't remember back far enough to say if LAB was available in PS4.

Alan

No is definitely the answer. I tried it and it just resulted in more colour noise.

Thanks for the comments.
Jim

Rich K 05-30-2008 11:36 PM

I used Photoshop Elements 5.0 until recently for post-processing, and in the Help section of the program regarding sharpening it states that one should create a new layer, change the new layer from "Normal" to "Luminosity" in the layers blending mode drop down box, and then sharpen that layer.

The specific text is . . .

"Sharpen your image on a separate layer so that you can resharpen it later if you need to change the adjustment. Set the layer’s blending mode to Luminosity to avoid color shifts along edges. If you find that highlights or shadows are lessened after you sharpen, use the layer blending controls to prevent sharpening in highlights and shadows."

The above was the method I used. Can't say whether it is as effective as the LAB color method, but it seemed to work for me.

River Rails Photography 05-31-2008 12:31 PM

One little tip is WATCH FOR HALOS...... they destroy images, and are caused by oversharpening an image........ you can detect them if you see thick white lines on your trains..... considering your train isnt passing a funeral :lol:


We HATE em.......http://bestsmileys.com/blobs/3.gif




sorry bout that one :roll:

a231pacific 06-07-2008 05:29 PM

Rich, it sounds like your Elements Luminosity sharpening is very similar to the LAB sharpening. I think lightness in channels is the luminosity channel, so you are doing the same thing via a somewhat different route.

Michael Allen


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