March 2017 - Digital Group - Blending Modes

Meeting Notes March 2009 to 2018.
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March 2017 - Digital Group - Blending Modes

Post by spb » Sat Mar 04, 2017 5:36 pm

Nikon are continuing to look for their place in the market. With the decline of compact cameras in favour of smartphones, they have abandoned a 1” high quality compact under development and will be putting more effort into high-end DSLRs and mirrorless cameras.

Suddenly, fleets of drones have become a ‘thing’. Intel have toured 100 drones worldwide and, more recently, 500 drones. They only carry a variable-colour light but can be controlled by a single laptop to arrange themselves in three dimensional patterns and text. I feel that this is going to be a big thing and there is talk of it becoming a more environmentally alternative to fireworks. Not to be outdone, the Chinese manufacturer of a drone have performed with 1000 drones! We can expect the fun-loving authorities to rapidly legislate against them (just imagine if fireworks were invented today). Here’s a video of the 500 drones.

It can sometimes be useful to create a contact sheet of thumbnails of a set of images. This can be done in several ways. Most easily and flexibly is with our brilliant free go-to image viewer Faststone (Win). Create>Contact Sheet Builder then choose the required images in the File List tab and options in the Settings tab. The Preview tab shows the result which can be saved as a JPG, PDF, TIFF or other document type.

Photoshop Elements can also create a limited Contact Sheet via the Organizer. The required images must first be imported, then choose File>Print>Type of Print>Contact Sheet. There are a small number of options, such as including file names, somewhat hidden under Show Print Options.

Photoshop CC can also achieve a similar thing, although in a more clunky manner with a long series of automated actions. Go to File>Automate>Contact Sheet II.

Another option would be a screenshot of any suitable layout of images from any app. The Windows Clipping Tool does the job….but overall, I would recommend the Faststone Contact Sheet Builder – it just works.

If we look at a reflection in water, for example, we are seeing two images in combination – the surface of the water, and the reflected view. Photoshop/Elements can do this too – and much more - by means of Blending Modes.

Before I start I should stress that knowledge of Layers is a prerequisite of Blending Modes and this is not a topic for beginners!

At the top of the Layers Palette, by default, is the word Normal. Click on this to reveal a list of 25 Blending Modes. For these to work there must be at least two layers. To try these out you will need a couple of layers, each with a different (and overlapping) image in it. The Blending Mode is always selected for the upper layer and determines how it blends with all of the visible layers below it. The results are never entirely predictable and it is usually necessary to quickly run down the list in order to find the best one for the required result. You don’t have to select each one in turn with the mouse - just click on Normal and then use up and down arrow keys on the keyboard to run though the list. The effects are never permanently ‘baked into’ the image and can be re-visited at any time in the layers palette of a .PSD file. Furthermore the strength of the blend can always be adjusted with the Opacity slider in the layers palette for any of the affected layers.

Opacity is in itself a sort of blending mode, but a very simple one. True Blending Modes are mathematically calculated and much more complex and interesting. They enable complex results to be achieve quickly without the necessity for selections.

The Blending Modes are divided into six groups in the list by horizontal dividers. Looking at these in turn;

1. The Normal Group – this is an odd group because the two modes have nothing in common! Other than Normal, there is Dissolve. This is a weird one because the upper layer must be partially opaque and the result is random speckles, the quantity of which is directly proportional to the opacity. I have used it to create noise and snow but there are better tools in the Filter Menu. Let’s quickly move on…

2. The Darkening Group – all of which produce darker and more intense results than the originals. Darken compares each pixel pair in the upper and lower image and simply chooses the darker one. This can be very useful for quickly adding a dark element eg a tree to a light background eg a sky. Multiply intensifies and darkens the combined image and is exactly analogous to putting two film transparencies in a mount together. Any dark area will mask the other image, any light area will allow it through. This is most useful for intensifying an image. Duplicate the layer and multiply the two identical copies. If this is too much, turn down the opacity. Color Burn is similar to Multiply but more saturated, Linear Burn is darker but less saturated and Darker Color is another variant of Darken. These can all be useful when blending a texture layer with an image.

3. The Lightening Group – all of which produce lighter and less intense results than the originals. Lighten is identical to Darken but chooses the lighter of the pair of pixels. This can be very useful for quickly adding light elements to a dark background eg fireworks to a black sky. Screen is similar and is exactly analogous to projecting the two layers from two projectors onto the same screen. Any light area will wash out the other image. Linear Dodge adds more luminance to the mix. I have found these to be useful now and again when adding highlights to dark subjects but it’s impossible to be more specific. Color Dodge is more contrasty and saturated, Lighter Color is another variant. Trial and error is the only way.

4. The Contrast Group – all of which produce a more contrasty result than either of the originals by lightening the lightest pixels and darkening the darkest pixels. The most useful are Overlay, Soft Light, Hard Light and Vivid Light. I actually use one of these on every finished image because I use them in High Pass Sharpening. See the explanation here and in the subsequent note below it. The Overlay mode can also be useful in, for example, adding a sunset reflection to water. A very effective editable burning and dodging technique is to create a new layer and then Edit>Fill Layer>50% Grey. Choose a Hard Light blending mode for this new layer and then using the Burning and/or Dodging tools on the grey layer will darken or lighten the image below whilst remaining reversible and editable. The final three modes, Linear Light, Pin Light and Hard Mix are more extreme.

5. The Inversion Group – produce negative colours. With Difference mode, black has no effect but lighter tones produce negative colours. Similar colours go to black. Exclusion mode is the same but similar colours go to grey. I have used these occasionally for highly creative results when blending textures with simple shapes but experimentation is essential. It may be necessary to make extreme levels and/or saturation adjustments to bring out the colours in the blended image. Subtract and Divide are even more extreme.

6. The Component Group – as their names suggest Hue, Saturation, Colour and Luminosity are exchanged between the two layers. The only purpose that I have found for these myself is with the fact that Adjustment Layers can also have blending modes (which may finally blow your mind). An extreme Levels or Curves adjustment may have the unintended by-product of increasing image saturation and this can be prevented by using them in Luminosity mode, which is a very handy tip.

So – I warned you that Blending Modes are not a beginners topic but once you are comfortable with layers, noodling around with the interplay of two very different image layers (perhaps a simple subject and a texture) can sometimes produce an interesting and unexpected result and be a spur to creativity.

Cheers, Steve Brabner

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