What is a simple and effective method to sharpen for web output in Photoshop?

Question

In Photoshop, I've got a master PSD image file with all mask and adjustment layer treatments, but no sharpening at all. I save for web and create a JPG at 1200px. Now, I bring that file back into Photoshop for some sharpening.

What's a quick and effective way to sharpen? I've read that using Filter -> Sharpen twice is good, but to me the outcome looks a bit over-processed. Is Smart Sharpen a better tool than just Sharpen? What about Sharpen More, Unsharp Mask, and Sharpen Edges?

Asked by RaffiM

Answer

There are a number of different lines of thought on this issue, and it seems that each one vehemently defends itself as the "one true way" to sharpen your image. In my experience, it comes down to personal preference and the specific image that you're working. Keep in mind that "sharpness" is really just an area of high contrast along an edge or line in your image. There are three primary methods that people use, but each have the fundamental effect of increasing this contrast:

1. Unsharp Mask - As I understand it, this was the "old" method for sharpening photos. Without going into too much detail, this method creates a blurred copy of the image and compares it to the original to determine where the edges are that need to be sharpened. This method has three options, Amount, Radius, and Threshold. Amount controls the intensity of the sharpening, radius controls the distance from edges that will have the sharpening applied, and the threshold controls how "different" two pixels have to be to be considered for sharpening. The unsharp mask in my experience tends to have a stronger effect than other methods, which I prefer, but some people don't.
2. Smart Sharpen - This method is the newer method for sharpening photos, with a bunch of different options. The Gaussian Blur option behaves similarly to the unsharp mask, but it also has the option to remove lens blur and motion blur. It has similar options to the unsharp mask method. I use this when I want to try to remove lens or motion blur, but I find that its Gaussian Blur sharpening isn't quite as pronounced as the unsharp mask.
3. High pass filters - This method is different than the other methods; it actually creates a second layer, and uses blending options to get a sharp effect on the edges. I don't like the appearance that the high pass filter gives to images, but I know a lot of other people prefer them.

The other filters (Sharpen, Sharpen More, and Sharpen Edges) I find to be less useful, because you have much less control over how they are applied to your image. But in some circumstances they may be appropriate.

This website has a really nice comparison of the high pass filter to the unsharp mask, and Ron Bigelow has a really detailed series of articles on each of the different sharpening methods. But I think the best thing to do is open up a few different copies of an image, apply different sharpening methods to each, and see which ones you like best.

Answered by David

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Which color settings to chose in Photoshop and Aperture with an Epson SPR2880 printer

Question

My workflow consists of importing photos into Apple Aperture, where I do most of my editing. Sometimes, I edit the photo in Photoshop. Aperture can automatically create a .psd file based on my edited image, and include that in its own library. The final results gets printed on an Epson Stylus Photo R2880 printer.

In the Aperture settings, I can select which color space to use when generating the .psd file. As I have set it up right now I use 16bit and ProPhoto RGB color space.

However, when opening up the color utility, I can see that some of the glossy paper color profiles for the printer contains colors that are not inside the ProPhoto RGB color space. This is mainly blue and purple nuances in the black area that are outside the scope of the ProPhoto RGB color space.

What puzzles me is that the icc profiles for my printer, an Epson Stylus Photo R2880 are not CMYK, but RGB profiles, I am wondering if I should choose one of the color profiles for that printer when exporting to PhotoShop. The annoying part about that setup is that I would have to go into Aperture preferences and select the export color space based on the papertype I wish to print on before opening an image in Photoshop.

What also puzzles me is the fact that the icc profiles for the printer use the RGB, not the CMYK, color space. Although the printer does have 8 instead of 4 types of ink instead of 4, it is still based on subtractive color, as opposed to additive color that the RGB space is.

I'm quite new to the entire color management thing, and I want to set up my system to be able to generate predictable prints, and also fully utilizing the capabilities of my printer, e.g. I can see by comparing the color profile of my monitor with the color profile of the printer that the printer by far exceeds the monitors capabilities in producing very saturated green and blue colors.

My primary workstation is an iMac, on which I have calibrated the display using a x-rite Colormunki.

Asked by Pete

Answer

Working color spaces and print color spaces are distinct, separate things. Generally speaking, you never want to directly apply a print profile to an image. The purpose of ICM is to utilize ICC profiles to describe what needs to be done when moving content from one device to another. You NEED to keep your photos tagged with an RGB ICC profile that properly describes the image in the RGB space, and you NEED to select an additional ICC profile that properly describes the capabilities of the printer. The ICM engine will then (normally) figure out how to adjust colors...according to your selected rendering intent...from the RGB space to the printer space.

To demonstrate my workflow, I generally do the following:

1. Do primary processing in the largest RGB color space I can (normally ProPhotoRGB).
2. Create a copy of my primary working image, and convert to an RGB color space that as closely matches the gamut of the print as possible.
   • This may be sRGB if the paper is a limiting factor.
   • This is often AdobeRGB, as my Canon PIXMA Pro9500 II supports a gamut that largely covers the AdobeRGB gamut
3. Manually scale the print copy to the exact dimensions necessary to accommodate my print.
   • If printing at 300ppi @ 19x13", I would scale and crop the image to 5700x3900 pixels.
   • Perform any print sharpening necessary to bring out desired detail
   • Preview at "print size" using the zoom tool (make sure you configure Photoshop with an accurate screen PPI...the Apple CinemaDisplay 30" has a 103ppi resolution)
4. Soft-proof the print in Photoshop, by selecting the appropriate printer ICC profile that matches the printer AND paper I intend to use
   • First and most importantly, I try to adjust black and white point to lie within the limits of the print gamut
   • If necessary, more so when using Relative Colorimetric rendering intent than Perceptual rendering intent, fix out-of-gamut color (search the web for a variety of techniques for this)
5. Print, leaving the image profile what I selected in step 2, and selecting the same ICC print profile as in step 4

I want to stress at least checking the white and black points when in soft-proofing mode. Using a Perceptual rendering intent when printing will usually do a pretty good job, but its easy to lose a lot of tonality in the shades and sometimes in the highlights if you don't adjust them for the specific printer and paper you intend to print on. Adjusting them in soft-proofing mode ahead of time helps maximize tonality for print. Generally speaking, you don't need to worry about out of gamut colors if you convert to an RGB space that closely matches the printer space. With modern Epson printers, that is probably closer to AdobeRGB than sRGB. If you prefer to use Colorimetric Rendering intent, then you might want to learn some techniques to fix out of gamut colors before printing, to maximize your control over color quality and minimize posterization.

Finally, once you have tuned the print copy for the specific paper and printer, save it with all your adjustments. You should be able to print from it as many times as you need with predictable results. If you ever need to print on a different printer, paper, and paper size, you should redo steps 1-4 above for each one, and save a separate copy off for each.

Answered by jrista

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How to compute luminous intensity in a photograph?

Question

I have a photograph in raw format taken by a Nikon D-90 camera of a white LED spotlight shining on a wall in an otherwise dark room. I need to compute the relative luminous intensity of the bright center of the spotlight which is much brighter than the diffuse area around it. The reason is that I am trying to compute the maximum candelas of this spotlight from its lumens rating for that bright center area. I would like to know what percentage of the total light emitted (530 lumens) is going to the bright spot in the center since from that I can compute the candelas by dividing the fraction of the lumens that go to the center by the steradians of the center bright spot. I have Photoshop CS5 extended to examine the photograph. How can I get an approximation of the luminosity ratio of the brightness level in the center to the brightness of the whole area illuminated to compute this?

Will the RGB values of the photograph be a linear scale or some kind or logarithmic scale? If I can figure the relative brightness at a particular location, I could use the area that has that brightness level

Answer

The raw RGB values are in a linear scale. Beware however that the RGB values of the rendered image are far from linear. I don't know whether Photoshop will let you access the raw RGBs, but you need them to do the computation.

To compute the intensity, you first have to integrate the whole spotlight, i.e. add all the pixel values. Divide this sum by the average pixel value at the bright center (averaged over an integer number of 2×2 blocks). You get something that I will call N which is equivalent to a number of pixels, i.e. you can say that the whole spot has as much light as a notional spot of uniform brightness (equal to the maximum brightness of the real spot) and extended across N pixels. From the geometry of your setup, you can convert this number into a surface area S = N × S_p on the wall, where S_p is the wall surface corresponding to one image pixel. From here you can get a solid angle Ω = S / d², where d is the distance between the LED and the wall. Ω is given in steradians.

Finally, your answer is I = Φ/Ω, where Φ is the luminous flux un lumens and I the luminous intensity in lumens per steradian (i.e. in candela).

All this assumes that the distance from the camera to the wall is significantly larger than the spot diameter. Otherwise you would have to throw some cosines in the integration.

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Why does Adobe Photoshop discard certain EXIF fields?

Question

I'm shooting on a Canon EOS 5D.

The images that come off the camera have some EXIF data (viewable in Irfanview), such as Camera Serial Number, Firmware Version, File Number, and Camera Temperature.

When they are processed with Adobe Photoshop CS5 (not tested any other version of Photoshop), some of the EXIF data is lost.

Even a simple open, resize, Save As... > JPEG causes this behavior.

Much of the EXIF is retained (about 50%), but certain fields, including those listed above, are always discarded.

This happens whether shooting in JPEG or RAW mode. What gives? And why only some fields?

The "Quality: Fine" (for JPEG mode) and "Quality: RAW" (for RAWs) is also lost.

The Make, Model, and DateTime fields for example, are preserved.

Answer

EXIF is a standard that programs such as Photoshop support. Within the standard is a reservation for 'Maker Notes' or custom EXIF fields that camera manufacturers use for a variety of reasons (such as shutter count in Canon 1D series). Many of these Maker Notes are used by the camera manufacturer for internal purposes, and while exposed within the image, are not really intended to provide any externally useful data.

Some online communities and the occasional program, such as Infraview, have deciphered (or think they have) some of these Maker Notes, and will reveal them. However, since they are not part of the standard, they can be changed at any time by the camera manufacturer, without warning. And of course, they could be entirely wrong.

I suspect Photoshop supports the EXIF standard, but does not expose the Maker Notes. The EXIF isn't missing, it just is not exposed in PS interfaces. Its possible that PS does not write into these Maker Note "slots" and the effect is 'lost' data.

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What's the professional approach to removing noise from a cell phone pic?

Question

I have a cell phone photo that's a bit grainy and slightly blurry. It's not the out-of-focus type of blur, but the blur brought on when edges run together due to lack of sharpness.

I have Adobe Photoshop CS5 and have used Filters > Noise > Reduce Noise. After playing with the options, I finally got a decent look. The options I used are Strength:5, Preserve Details:0, Reduce Color Noise:0, Sharpen Details:100.

Are there other more effective ways to remove grain noise and blur from a cell phone pic? What would the pros do provided they use CS5?

Answer

These days, I would think pros use tools like Adobe Lightroom as much as Photoshop. Lightroom 3.x specifically is particularly well suited to removing noise as it uses a newer, more advanced algorithm to do so. It may also be the case that the latest version of ACR (Adobe Camera RAW) for photoshop has the same noise reduction tools if you happen to be using RAW. Lightroom will work with JPEG images as well as RAW, however, so its advanced noise reduction should still be viable for a cell phone photo. Lightroom is quite a bit cheaper than Photoshop as well, currently listing at $299.

I would say a moderate amount of luminance noise reduction, 60-80, would be sufficient to clear up a cell phone pic to reasonable levels. I would still throw back in some sharpening, to offset the effects of noise reduction and the blur (which is probably diffraction softening, given that it was a cell phone photo...they tend to have excessively small sensors with extremely high MP count, which when paired with the incredibly small apertures for the tiny lens, usually results in a fair amount of diffraction softening.) As far as sharpening tools, Lightroom's is ok, but not superb. Photoshops Smart Sharpen filter is probably one of the better sharpening tools. There are also a variety of other manual sharpening techniques that you can find around the web that involve various layer duplications, inversions, filtrations, and blending modes to achieve. Some algorithms and procedures are better for some types of photography, while others are better for different types of photography (i.e. how you sharpen a landscape would be different from how you sharpen a portrait.)

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Does the 'Other Dynamics' brush option exist in Photoshop CS5?

Question

I have CS3 on one computer and CS 5 on another. On CS3 my dynamic brush options have a section called 'Other Dynamics' that allows me to change jitter opacity, but my CS5 does not have that option in the same area.

Does CS5 not have 'Other Dynamics' for brushes or is it just somewhere else?

Thanks

Answer

Go to the Brush panel (Window -> Brush, or F5), select the "Brush" tab. You will find "Opacity Jitter" in the "Transfer" section.

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