Simple reasons why we use Photoshop 1/2
This quick guide is a combination of lesson sheets you may want to have by your side when using Photoshop. This is part 1 out of 2 on Photoshop’s lesson sheets.
When a picture is to be printed: use inches (300ppi).
When a picture is to be NOT printed: the usage of pixels is prefered.
It is a mode on photoshop that helps to realize mockups of websites or mobile apps.
Customization of panels’ appearance
The preferences can be changed (i.e. the organization of the dialog box).
Customization of tools’ appearance
As the tools usage depends on the projects, the customization of the tools’ appearance is helpful. Moreover, it can also be time saving to register the customizations as presets in photoshop.
Any type of customization in photoshop helps to suit working habits (i.e. adding and removing keyboard shortcuts).
- Customizing workspace,
- Darker and/or lighter interface,
- Working easily with different images in photoshop or focusing on a single one.
Various selection tools
The availability of numerous selection tools helps to refine the selection wanted to achieve the aim goal and get organized with layers.
2 main file types exist:
1 Bitmaps made of pixels. In case of a zoom, the image will be degraded.
2 Vectors. They can only support fewer colors but in case of a zoom, the image will not be degraded.
After having seen this 2 main differences, the focus can now go on the formats available:
- GIF: contains only a few colors but does not lose quality. As there are 256 colors only, this format is not consistent for photography.
- PSD: contains all the information of the project and all the layers. However, it may be too large.
- RAW: contains a lot of information from 1 photo. The only problem is the file size: 4,5 times larger than another photo format.
- Camera Raw plugin: Canon CRW or CR2;
- Nikon: NEF or NRW;
- Basic: DNG (open source)
- JPG: reduces file size but loses information. An enregistrement as JPG is a 1 time event only.
- PNG: compresses but loses less information as JPG. An enregistrement as PNG maintains colors and transparency.
- EPS: is a printer format. It is also a vector format, allowing high resolution printing.
- TIFF: looks like EPS but it is the non-vectorial type. As it is a Bitmap image, it allows lower resolution printing but is more flexible.
3 outputs are to be known. According to each, the resolution changes.
1 Pre-press. It uses halftones (pro printer) with CMYK dots. It is important here to talk with the printer to know the line screen and paper quality. And the resolution = 2*LPI (Line Screen given by the printer). As an example, if LPI = 85, the resolution needs to be at least 170 ppi (pixels per inch).
2 Inkjet/Photo. It uses continuous tones (photo printer at home). Here a try-and-error method between 240 ppi and 360 ppi is advised. Usually, a resolution around 300ppi is the safe bet.
3 Display output / On Screen (for mobile apps and websites). The resolution does not matter in that case, only the dimension measured in pixels is important.
Resize vs Resampling an Image
Those 2 words seem to be the same, but it is not quite so. Then, what is the difference exactly?
1 RESIZING is changing output of file
2 RESAMPLING contains 2 types:
- Upsampling to increase your image size. This procedure loses sharpness, max 15-20% bigger is doable.
- Downsampling to reduce the overall size (easier than upsampling).
For printing in a photo album, the common advice is to resample with the bicubic sharper algorithm (for reduction / downsampling).
There are 5 modes of color.
The 3 basics are:
- Bitmap: 2 colors
- Grayscale: 256 shades
- Index: 256 colors
The bigger modes are:
- RGB: millions of colors (256 power 3 because there are 3 channels)
- CMYK: millions of colors. This mode is the one to choose for sending to pro pre-press