Amersham Beyond Group - 7th Feb 2019

Meeting Notes on Creative Photography and Photo-Art
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spb
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Joined: Tue Mar 25, 2008 7:04 pm

Amersham Beyond Group - 7th Feb 2019

Post by spb » Sun Feb 10, 2019 2:46 pm

MONTHLY CHALLENGES

#2 ICE OR WATER CLOSE-UP

A varied set of about 25 images were submitted by members including close-ups of streams, snow, dewdrops, oil in water and soap bubbles; all technically proficient and interesting.

One popular theme was of flowers frozen in ice which four members attempted for the first time. We shared some tips that we had learnt in the process;
- de-ionised water (sold in hardware stores for steam irons and older-style car batteries) gives clearer ice than tap water
- the flowers create air bubbles as they are compressed by the ice but keeping the cut stem out of the water helps to prevent an excessive fog of bubbles
- lighting is key and light shining through the ice can give a beautiful glow to the petals
- a macro lens helps to get in close to the amazing detail
- the specular highlights on the bubbles can take stronger sharpening than usual.

The next Challenge will be;

#3 HIGH-KEY

I defined this as “having a predominance of light or bright tones with minimal shadows and little tonal contrast. This does not necessarily preclude small areas of dark or black tone”.

There are numerous examples of high-key images online for inspiration and I also offered some guidance for those attempting this technique for the first time…

In-Camera High-Key.
- simple graphical subjects are usually most popular and effective for this technique, although it can also give dramatic portraits
- a bright or white environment is a good start and makes for less work in the processing stage. Art galleries and snow scenes are obvious examples but a white backdrop on a table-top is equally effective.
- if taking JPGs, over-exposure in the camera can be employed but not so much that detail and any important blacks are lost in the primary subject
- ideally, using RAW gives the latitude to make extreme adjustments in post-processing
- control over lighting helps to create the light tones where you want them but not where you don’t
- it’s likely that some post-processing will be necessary to get the best effect and it’s possible to turn almost any image into high-key given enough time and effort in an image editor.

Post-Processing High-Key.
There are several techniques that can be used individually or in combination to lighten areas of the image with control;
- Levels or Curves adjustments are an obvious starting point. If you want no blacks or dark tones at all, the Levels output slider can achieve this easily. Using a Levels or Curves adjustment layer (rather than directly adjusting an image layer) is preferable as is gives a flexible, non-destructive, workflow
- Dodging with a low exposure setting and a soft-edged Dodge brush can lighten areas with great control. Dodging onto a new layer (above the image layer) filled with 50% grey and set to Overlay or Hard Light blending mode gives an adjustable non-destructive workflow
- duplicating the image layer and setting the upper copy to Screen or Colour Dodge blending mode creates an instant lightening of all tones except full black.
- ordinarily I would never use paint on an image layer as it has no natural texture or noise. However in this exceptional case, pure white paint is fine and is likely to be a large part of the finished image. Preferably paint onto a blank layer above an image layer rather than directly onto it.

The benefit of the above non-destructive options is that they can be adjusted for strength with the opacity slider and also for location with a layer mask without touching the original image.

Another approach might be to try some of the filters from NIK, Topaz Labs or similar, which give a High Key effect. Whilst this is not likely to give an instant result it can help to visualise the direction in which to go with an image. Don’t forget that the pre-canned presets are only suggestions and can be further adjusted by the many sliders. In this case, the High Key filters tend to be a bit tame and need boosting with more exposure/stronger whites etc.

OTHER CREATIVE WORK

Alison Trimbee showed us some first experiments with photographing smoke. Getting adequate tonal separation between the lighter tones of the smoke and the dark background was a problem and a fair amount of post-processing was necessary to achieve her excellent final images. As with the frozen flowers, the lighting is key. Alison has since bought some black velvet to reduce reflections of the lights on the backcloth. We look forward to future images.

THE BACK OF BEYOND – DIARIES

COLOUR SPACE / BIT DEPTH
As mentioned last month, control of colour space is important when sending images to somewhere that is not colour-aware (like the entire internet!). Getting a grip on this issue has proved elusive for at least one member, with images still being output in pesky Pro-Photo RGB.

Pro-Photo has been designed to be big enough to encompass any colours that any current professional camera can generate. By contrast Adobe RGB encompasses a smaller range of colours that the best screens or printers can achieve and sRGB is smaller again and contains enough colours for non-professional eyes and equipment ie the world at large.

As an amateur photographer with mid-range equipment, I found long ago that I could not see any difference between Adobe RGB and sRGB and by setting my workflow to sRGB I could ignore the whole thing. However, many photographers have settled on Adobe RGB as their preferred space. More recently Pro-Photo RGB has become the Lightroom default workflow. We need to be pro-active in ensuring that the whole workflow is set to our chosen colour space. An Adobe RGB image in a non-colour-aware environment just looks slightly desaturated but a Pro-Photo RGB image looks dreadful.

In addition to colour space, bit-depth can have an effect on image quality and if going for anything beyond sRGB we may need to increase the bit depth to 16bit rather than 8bit. This increases the number of possible colours from 16 million to trillions which seems like overkill except that any single colour can only have 256 tones in sRGB which can quite quickly result in posterization or banding after adjustment. With 16bit that figure increases to 65k. Unfortunately the price to pay is that file size doubles with 16 bit. If using Photoshop Elements, 16 bit files are not feasible as vital features such as layers and filters are not supported.

There’s a chain of possible settings to be aware of;

1. Camera. Set your camera to your chosen colour space. Many offer sRGB and Adobe RGB. This will determine the colour space of JPGs from the camera. RAW files from the camera are just a string of data with no colour space but there is sometimes an option to save RAW files at a lower bit-depth or with compression.
2. Lightroom CC Classic. Edit>Preferences>External Editing>Photoshop>set colour space and bit depth. Also in File>Export>LR Presets>File Settings> (for each file format you might use).
3. Photoshop CC – Adobe Camera Raw. If you use the Raw Converter in Photoshop (ie opening a RAW without LR) you need to set the colour space there – open any RAW file using Photoshop and on the Adobe Raw Converter screen click on the conversion specification at the bottom centre and set Color Space and Bit Depth here.
4. Photoshop CC -Editor. Go to Edit>Color Settings> …. (North America General Purpose 2 here is good for sRGB). Also if necessary Image>Mode>Bit Depth to change the Bit Depth of the current image only.
5. Photoshop Elements. Go to Edit>Colour Settings. Here ‘Computer Screens’ sets sRGB and ‘Printing’ sets Adobe RGB. Note that Photoshop Elements has next-to-no support for 16 bit files.

When you are editing in Photoshop, you can see that you do indeed have your required colour space by going to File>Save As… and the profile of the open image will be stated there. If you need to convert an existing image that’s in the wrong space you can go to Edit>Convert to Profile. Here it will tell you the current (source) space and you can set the Destination Space. Converting the Colour Space is unlikely to change the look of an image significantly. However, never use Edit>Assign Profile – that’s a quick way to mess up your image!

Why is it so complicated? Unfortunately our technological world has been designed by nerds without adult supervision.

The only time that I have questioned my decision to stick with sRGB and 8 bit is when I have made extreme tonal adjustments and occasionally seen banding. I have also rarely produced images with extremely saturated colours that might benefit from the greater Adobe RGB space. However, my recent frozen flower pictures do indeed have highly saturated colours so maybe I should take more notice of image quality in this instance in future.

EVERYTHING SEARCH (Windows)
The search function in Windows has always been a disappointment. Somehow it always manages to fail to find what I want or suggests internet sources when I don’t want them. Despite supposed improvement in Win10, customising the search indexing, and fiddling with the settings, I remain disappointed.

I have now largely abandoned Windows Search in favour of a brilliant, simple example of freeware called Everything.
This searches file and folder names instantly as you type letter by letter and covers everything on the computer, without exception. The initial indexing process takes seconds and it all just works! It can search within files as well but this is not indexed so is slow unless you limit it with a file name filter as well.

I run the ‘portable’ version which does not install itself in the registry or embed itself in the operating system at all. Highly recommended.

iPHONE TRACKPAD MODE
iOS12 introduced a brilliant little feature that users may well be unaware of. When typing anything on an iPhone or iPad keypad, press and hold the spacebar. After a second the keyboard will blank out and sliding your finger will move the cursor anywhere on the screen like a trackpad. This is so much easier to use than trying to position the cursor accurately by tapping on the screen, as before. I believe that Android has a similar feature.

Cheers, Steve

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