May 2009 - Digital Group Mtg - Sharpening

Meeting Notes March 2009 to 2018.
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spb
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Joined: Tue Mar 25, 2008 7:04 pm

May 2009 - Digital Group Mtg - Sharpening

Post by spb » Mon May 25, 2009 6:44 pm

Our last meeting of the season looked at sharpening and also more thoughts on image management software

NEWS

dpReview have continued their excellent series of group camera tests with Compact Superzooms. If you are thinking of buying a compact or sub-compact camera for the summer you would do well to look at their group tests also covering Superzooms, Enthusiast Compacts, Premium Compacts, Ultra Compacts and Budget Compacts.

Silver Efex Pro (199 Euros) has been updated to include a plug-in for Lightroom. This software specialises in the conversion of colour images to monochrome and can simulate 18 b&w film types including the emulation of silver halide grain effects.

SHARPENING

Alan Cross kindly agreed to repeat a talk on Sharpening that he had prepared for the RPS. Summarising his talk;

Sharpening adjusts images to a) overcome shortcomings of the capture process, b) achieve creative expression and c) overcome shortcomings of the printing process.

Unsharp Mask (USM) is the best sharpening tool in Photoshop/Elements. Initial capture sharpening may be done by the camera, by the Raw conversion software or ideally by USM, but should be relatively modest and not increase the visible grain. Any stronger sharpening for creative or printing purposes should be done at the end of the image manipulation process to avoid creating undesirable artifacts. A layer mask may be used to sharpen areas of important detail but not background areas or skies. A good process would be to save the layered image after creative sharpening and then create a flattened copy for one-off output sharpening which may vary from printer to printer and paper to paper. Matt papers tolerate much more sharpening than gloss papers for instance.

Perhaps the biggest lesson to learn is that it's impossible to judge final prints from the display. You must often make a leap of faith and send pixels that look hideous on screen to the printer. If they don't look seriously 'crunchy' on screen you're almost certainly under-sharpening your images. The only way to evaluate print sharpening is to print it and look at the print. Furthermore images must never be re-sampled after output sharpening. ie the Image Size>Re-sample Image tick box must remain unticked once output sharpening has been applied.

In USM the Amount slider controls the quantity of sharpening by (arbitrary) percentage, the Radius slider controls the width of the sharpening either side of an edge and the Threshold slider controls the level below which image detail will not be sharpened ie to avoid sharpening grain or skin pores whilst still sharpening the major features. There can be no rules for the use of these controls which will vary from image to image and will depend on your desired result.

A popular alternative to USM uses the High Pass filter. Make a copy of the layer to be sharpened. Apply Filter>Other>High Pass to the upper layer at a fairly low setting which just reveals the edges to be sharpened. Change the blending mode of this layer to Hard Light. The amount of sharpening can be reduced with the Opacity setting for the layer. It can be increased by duplicating the layer.

Alan recommends PK Sharpener ($99) which adopts the three stage approach but removes a lot of the guesswork. Nevertheless, you still have creative control. Beware that file sizes can become large if you choose to keep all of the sharpening layers created by the automated process.

Alan finished by passing around sample prints. The results were certainly impressive and gave rise to the thought that we could all pay more attention to sharpening in the future.

IMAGE VIEWING AND CATALOGUING SOFTWARE

LIGHTROOM - Further to my analysis last month I decided to delete my Lightroom Catalogue. After a year of playing with Lightroom, I was shocked to find 12,000 files in 15,000 folders as well as hundreds of .XMP files dotted about. By deleting everything I recovered over 8GB! It should also be noted that casually choosing 'Edit in Photoshop' creates a duplicate file of many tens of MBytes which will live on you hard disk for ever unless cleared out. In future I will create a catalogue for specific projects and then delete it.

FASTSTONE AND XNVIEW - Several members have tried FastStone and the reaction has been universally positive. However I have identified a couple of issues; if a .PSD file has any additional channels such as saved masks or selections these can obscure the thumbnail and preview. Also the time to load full size previews of Raws is quite slow at several seconds per image. Unfortunately neither author has responded to my emails. Nevertheless I will continue to use these viewers over the summer as they are the most attractive and functional images viewers that I have found ....and they're both free!

MY COMPUTER REPLACEMENTS - Neither FastStone nor XNView are capable of being full replacements to My Computer/Windows Explorer. Looking for such a product I came across Directory Opus (£42) . This far exceeds the capabilities of My Computer - if anything, perhaps it tries to do too much. Although not intended as an image viewer, they are thumbnailed and previewed well but there are no facilities to edit images or pick selections. It is also not colour-aware. Nevertheless if you are frustrated by the limitations of My Computer you might take up the generous 60 day free trial.

NEXT MEETING

The next meeting is on October 8th. Have a great summer and as always, I would welcome any feedback on these digital group meetings.

Cheers, Steve Brabner

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