May 2014 - Composite Images

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

May 2014 - Composite Images

Post by spb » Thu Apr 24, 2014 8:58 pm

NEWS

Windows XP;
Microsoft have ceased to support XP and Internet Explorer 8 which means that they are likely to be targetted by scammers, so users should consider upgrading to Windows 7 or 8 if their hardware is adequate or replacing their computer. At the very least, they should use a third-party virus protection that continues to support XP, and change to using an alternative browser such as Chrome or Firefox.

It's not re-assuring that an estimated one third of computers worldwide still run XP, as do most cash machines and much of the UK government!

London Live;
Interestingly, this new local TV station on Freeview channel 8 has been equipped with Nikon DSLRs instead of broadcast video cameras. D4's are used in the studio and D800's on location.

Raw Digger (£12+);
The more analytical amongst you may have wondered about the exact workings of Raw files. Raw Digger is a raw image analyzer which enables you to do exactly this. One example of how this might be useful would be to examine exactly how overexposed an image actually is when the highlights start to blink on the camera display. Is there still headroom available? This could be useful as we are told that we should 'expose to the right' ie increase the exposure as far as possible to capture the maximum tonal information in the file. The histogram on the camera is only a guide and cannot be relied upon.

Cloud Storage;
Thanks to member Peter Mukherjee for pointing us in the direction of BackBlaze which promises unlimited online storage for just £3/month.

This seemed to me to be in the 'too good to be true' class! So a bit of research revealed that the file types accepted have some exclusions such as disk images and exe files, but more significantly, the transfer rate is somewhat limited. They offer a speed test which for me quoted 24GB/day which is a fraction of the capability of my Infinity broadband line.

Nevertheless, this could be a very good option for backing-up modest quantities of images and documents but I will continue to use local external HDDs as my primary bckups.

COMBINING IMAGES IN PHOTOSHOP ELEMENTS

Apologies to the Lightroom users amongst you, but this is not for you. An image editor such as Photoshop Elements is needed for this kind of manipulation.

For example let's assume that we have taken several images of an interesting scene but no single image contains all of the best bits. So we need to combine bits from two (or more) images……

1.Achieving a Single File;
Firstly we need to move both images into a single file. There are several ways to do this;

a) open the first image, then use File>Place to open the second image as a new layer above it. NB you need to hit Return to 'commit' the placing of the second image.
or,
b) open both images normally, then choose Select>All, followed by Edit>Copy. Close the top image and in the remaining image choose Edit>Paste.
or,
c) open both images normally and drag the top image header down to partially reveal the second image below (NB if you can't do this you may need to go to Edit>Preferences>General and tick the box to 'allow floating documents in Full Edit Mode). In the Layers Palette, click on the Background layer's thumbnail then drag and drop it onto the other image.

2.Layer Masks;
We now need to hide the part of the upper image that we don't want. With the upper layer active, choose Layer>Layer Mask>Reveal All. Set the foreground and background colours to their defaults of black and white (keyboard shortcut D) and choose the Brush Tool. In the Layers Palette, click on the white masking box for the top layer and paint onto the image. Black will hide the image or switch to white (keyboard shortcut X) to reveal it again. Finally use the Move Tool to place the remaining part of the upper image in the required position.

As an alternative to using the brush, another useful tool for creating a mask is the Gradient Tool. With black and white as the foreground and background colours, choose the Gradient Tool and set it for a foreground to background, linear gradient. Click on the white masking box for the top layer and then click and drag in the image. This will create a black to white gradient which hides the upper image along the line of the gradient. If the wrong half is revealed, drag again in the opposite direction. If the edge is too sharp, drag a longer gradient. If the position is wrong, drag repeatedly until it is exactly where you want it.

The layer mask can also be modified further with black, white or grey paint on a brush. If you are feeling ambitious, extra gradients can be added onto an existing mask by using a foreground (or background) to transparent gradient.

Other useful shortcuts for layer masks are;
Shift+click on the mask to hide it (repeat to reveal it again)
Alt+click on the mask to show it on screen (repeat to hide it again)
Right-click on the mask for other options.

3.Adjusting Individual Layers;
Having assembled a composite image with two or more components, each on a layer, it will often be be necessary to blend them together visually. Adjustment Layers offer the usual range of tonal and colour adjustments but they normally affect all layers below them in the layer palette. To limit an Adjustment Layer to affect just one image layer, Alt+click on the boundary between an Adjustment Layer and the image layer below it. This creates a so-called 'clipping layer' and the Adjustment Layer becomes indented as a reminder.

There are other ways to achieve a composite but the methods described above are reversible and enable changes to be freely made at a later date, so long as the image is not flattened and is saved as a .PSD.

NEXT MEETING

This is the last meeting of the 2013-14 season. See you again in October 2014!

Cheers, Steve Brabner.

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