This article will explain the importance of evaluating your image at different “zoom levels” while you work.
How an image is perceived is largely dependent on the viewing distance and the physical size of the image canvas.
It is easy to forget, but what you see up close is not what you see from afar. For example, when you stand close to an oil painting, you are able to see the canvas texture and brush strokes. If you take a step back, you no longer see those small details – what you see is not the same as before. Take another step back and the visible details change yet again.
When we talk about texture, we usually refer to a surface and its characteristics.
How we perceive a subject’s surface in photography very much depends on the characteristics and direction of the light. An uneven surface under a harsh side light will have higher contrast between shadows and highlights than the same surface under a soft and/or non-side light.
Some may mistakenly believe that texture is only referring to the details on the smallest level, but this is not true. Texture is the whole surface and its characteristics regardless of viewing distance.
Image resolution and pixel density
Image resolution can be defined as the number of pixels available in both height and width. A high image resolution means there is more image data and, with that, more detail recorded in the image.
When viewing digital images, not only does the image resolution matter, but so does the screen resolution and the size of the screen itself. We must also take into account the distance between the viewer’s eyes and the screen, or viewing distance.
All of this defines how much detail the viewer can see and how the image is perceived.
For example, today’s cell phones have high resolution (high pixel density) displays, but the screens are often very small, so at the normal viewing distance you will not see the small details of an image.
The Megapixel race
Modern camera manufacturers are consumed by the race to deliver the highest camera sensor resolution, which is commonly measured in Megapixels. Modern cameras allow you to take photos with enough color and detail information to make very large prints that won’t look pixelated even up close.
Unfortunately, digital displays do not come close to providing the same level of performance. So, unless you aim to print your images at very large sizes, you normally have no use for all of the extra information in the photo files – information which may even be a burden (but more on that later).
In addition, most digital images are viewed on the Internet, where they are sized down considerably to conserve bandwidth.
Facebook has a maximum allowed resolution of 2048 x 2048 pixels (4 megapixels), but the format of most images is not square, so realistically, the size is more like 2048 x 1365 pixels (2.8 megapixels).
Even if we don’t take the Facebook restrictions into account, the most common screen resolution is 1280 x 1024 pixels (1.3 megapixels.), so when you’re looking at an image with a higher resolution, you’re still seeing the resolution of the screen. Which means if you showcase your images digitally, it is safe to assume that a lot of your image data is lost on the way to the viewer.
The Frequency Separation trap
This technique has gained a lot of ground lately and is very popular among retouchers and photographers who retouch their own images. In short, the technique splits the image into two frequencies: small details go into one layer (High Frequency layer), and the colors and tones of the image go into another (Low Frequency layer).
However, this is a huge trap! As explained previously, texture exists not only in the fine details but also across the whole surface of an image. So even if you keep all of the apparent detail in the high frequency layer, at a certain viewing distance (or at a lower resolution) when the small details are no longer visible, if you have over-retouched the low layer, you will have lost all texture in the image, resulting in a blurred image.
Many beginners struggle with this problem by trying to correct too much on the low frequency layer. It is important to understand how these layers work together to display texture at different viewing distances and resolutions in order to make good images.
The image above illustrates that even though details are removed, both of the images look almost the same when zoomed out.
The image above illustrates how easy it is to over-retouch when you are zoomed in. The first image looks almost the same in both versions, but as soon as the image is zoomed out, the bottom one looks too blurred.
So what does this mean practically?
This means you have to be aware of how your image will look at different resolutions and at different viewing distances.
– Work on large details zoomed out and fine details zoomed in: zoom in and out as often as possible.
– Never stay at 100% view for too long.
– Evaluate your changes on a global level, with the whole image visible.
You can add a New Window of the image you’re working on to your workspace, zoom it out and you will see the changes applied as you work on the same image in a different window zoomed in (Window/Arrange/New Window for …). You can also jump between the two windows and work on your image at two different zoom levels.
– The higher the resolution your working file has, the more detail levels the image contains, and the more discipline with zooming in and out you will need to have while retouching it.
– Always remember to adjust your retouching workflow for the intended target.