Photoshop - Converging Verticals
This involves the use of the Free Transform technique. Normally do this before any other actions, as you may have to crop afterwards (which is also a good time to set the size and resolution). Transform only applies to the Active Layer, ie the one in the Layers panel with a blue background.
- If you have just loaded a jpeg on screen, then it will appear as Background in the Layers Panel. You can not transform a Background, so convert it to an Image Layer by double-clicking the word Background on the Layers Panel, renaming it and clicking OK. Alternatively, hold down the [Alt] key and whilst doing so, double-click the word Background in the Layers panel. It will change to Layer0. (See Fig 2)
Now maximise the
image by clicking on the centre icon of the min/max/close icons (right)
and then zoom out until you can see all four sides of the image. (Hold
down [Alt] and use the Zoom tool) - Set the Free Transform mode from the Edit Menu or by holding down the [Ctrl] key and pressing [T]. A line with 8 grab handles should appear around the image. There is also a centre point which is the pivot for rotation. You can grab and reposition this if you want. (See Fig 3)
- This is a very powerful feature. You can distort the image in many ways by grabbing one of the handles with the mouse and moving it. Try it in conjunction with the [Shift] key, the [Ctrl] key and the [Alt] key, and with combinations of these. You can rotate the image by positioning the cursor a little way outside the image (its probably easiest under the middle bottom handle) until it turns into a bent double-headed arrow. Now hold down the left mouse button and rotate the image by moving the cursor to left or right.
- Click on the Tick on the right hand side of the Options Bar to accept, or on the Abort sign next to it to reject. You can also accept the change by double-clicking INSIDE the image.
- However, To STRAIGHTEN VERTICALS, (which usually show convergence to the top Fig 1) hold down the [Shift] and [Ctrl] keys and move the top corner handles outwards (the [Shift] key limits the movement to horizontal). You can do one or both sides separately this way or both together if you hold down [Shift] [Ctrl] [Alt], and it may be best to leave just a little convergence in place particularly on a close-up shot of a tall building. Click on the Tick on the right hand side of the Options Bar to accept, or on the Abort sign next to the tick to reject. You can also accept the change by double-clicking INSIDE the image.
Images taken with
digital cameras are particularly prone to converging verticals because
of the small size of the detector and the correspondingly short focal
length of the lens. The more you have to tilt the camera upwards, the
worse the effect. This image of the 3 Graces at Liverpool Pier Head
exhibits severe convergence particularly near to the camera position,
so each side of the image will require a different degree of
correction.
Fig 2 (left) shows
the
Layers Panel after conversion from Background to Image Layer. (I have
used [Alt] and double-click.) and Fig 3 (right) shows the image after
applying
[Ctrl]+T, complete with 8 grab handles, ready for the verticals
adjustment.
Fig 4
(left) shows
the image after dragging out the top corners (using [Shift][Ctrl]) by
differing amounts until the desired effect is achieved.
Unfortunately, part of the Port of Liverpool building has been lost. Must remember this next time I take the shot.
The Free Format technique also works on other Image Layers, eg. one which is perhaps a copy of a part of the main image or maybe has been imported from another image or even is a piece of clipart loaded into a separate layer.
Make sure that the layer you want to work on is Active ie the name area on the Layers Panel is blue.
- Initiate the Transform mode by pressing [Ctrl]+T. A box with 8 grab handles and a centre point should appear around the image.
- The centre point is the pivot point for ROTATION and you can drag it to a different position, even outside the image area. Rotate the layer by positioning the mouse cursor outside the transform box so that it becomes a double-headed bent arrow, and then moving it to left or right. Click on the Tick on the right hand side of the Options Bar to accept, or on the Abort sign next to it to reject. You can also accept the change by double-clicking INSIDE the image.
- You can RESIZE the image layer by manipulating one of the
corner handles.
- With the mouse pointer alone, you can change the size and aspect ratio.
- With the [Shift] key held down, the aspect ratio is maintained and just the size changes
- With the [Ctrl] key held down, you can change the size, the aspect ratio and the skew.
- A whole host of possibilities are available on the EDIT MENU, Transform, including all of the above plus flipping, rotating and perspective.