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Introduction to photofiltre


1.Installing

We will use the free version of photofiltre.

photofiltre EN languages packages

Once downloaded, installing photofiltre is easy.

First lauch the installator : accept the terms of the License Agreement (you can read it for this time, it's not too long) which tells you that you can't use photofiltre for commercial issues, only in a private of educative situation … Fortunately I don't force rules, so we can continue this tutorial.

2.Basics

Like in every edition software, you can open a file, save it, create a new one, etc … These commands are available in the “File” menu as here :

Remember the keyboard shortcuts, once known they allow you to spend less time. Most of these shortcuts are available in most of the softwares (at least with windows).

I won't explain open and save function which you should already know. Take a look at the “new…” function, shortcut ctrl+N :

It's no use to explain what are width and height … you can modify the unit used for them but it's useless for us. The color displayed with “Background” is the color which is used for the new picture's background. By default it's white. Background pattern allows you to put a picture in the new picture, it's useless for us. The preset sizes allows you to choose a usual size like CD jackets for example. Once again it's useless for us.

So no surprise in this menu.

3.Tools

First it's important to know how to zoom, it's displayed at the top of the screen :

The menu displays the ratio of the displayed size and the real size (100% is for real size), the magnifying glasses next to it allow you to zoom in and out. The third icon displays the picture in real soze (zoom 100%), the next one displays the picture in automatic size (100% if the screen is large enough, small enough to be entirely displayed otherwise) and the last icon displays the picture in fullscreen.

It's possible to zoom in and out with the mousewheel, so it's much easier. Notice that the third mouse button (usually click on the mousewheel) used when the cursor is inside a picture, will place the picture at the top left of the scren in automatic size.

After having created a void picture with the previous menu, we are going to test basic tools available in the tools'menu on the right of the screen :

These tools will be explained here or below. the first (top left) is the selection tool, will be explained below. Next to it is the pipette tool which allows to take a color directly on a picture.shortcut : keep ctrl key when clicking on the picture. Then, the magic wand is explained below, then there's the line tool which is explained below as the fill tool, the spray tool allows to draw with a spraycan (with dispersion), then the paintbrush tool is explained below, the advanced paintbrush tool just gives some patterns more for the paintbrush tool, useless for us, the blur tool is for blur some parts of the picture, the smudge tool is like you put your big fat fingers on the picture, the clone stamp tool is explained below, the scrolling tool allows you to scroll the picture as if you scrolled on a .pdf file.

The magic wand tool

Clicking on a pixel with the magic wand too makes a selection with the pixels of the same color or near this color. Tick the case “Color” selects all pixels of the picture which are of the same color or near it.

The line tool

Of course, it makes lines and it's one the most important tool to know.

The width is the width of the line, there it's two pixels by default. The opacity is to make a transparent line if it's lower than 100. Antialias is an automatic anti aliasing, it's sometimes usefull or useless.

The arrows are for making arrows, usefull to point somthing on a picture for example.

Lines'coordinates are displayed on the bottom of the screen, they allows you to make lines very precisely.

The fill tool

It allows to “fill” a part of the picture depending on the color where you click.

It has several parameters :

As you can see on the penultimate picture, the fill tool fills the color where you click and the colors which looks like enough to the first color. The tolerance parameter adjusts the max difference between the first color and the others colors to be filled. The opacity allows to fill transparent, an opacity equal to 100 will completely replace filles colors.

Use a 0 tolerance is usual, when you use fill tool or other tools using tolerance, check that it's at the level you want …

The paintbrush tool

It contains several patterns, most of the time we will use the dot pattern to modify small parts of a picture.

The dot is selected by default, it's a single pixel. It's usefull to modify small parts of the picture which we zoom on. This tool has a real precision to modify only some pixels. The second pattern, next to the first one, can be used. As most of the patterns here, its shape isn't net so it uses transparency (good thing to know …). The two patterns at the bottom left have variable radius, you can see the cell allowing to adjust this radius, just below.

The clone stamp tool

Even if we won't use this tool, it's good to know it. It copies parts of the picture on other parts. Once selected, keep ctrl key clicking on the part you are going to copy, your stamp will stay here until you redefine it elsewhere. The nearby part of the picture will be reproduced where you will click then. The radius of the stamp is variable. If you tick “fixed” the stamp won't move when you use it. The opacity allows you to adjust the transparence of the stamp, higher it is less what you reproduce will be visible. A 100 opacity will do a stamp completely opaque.

The other tools which aren't explained yet will be explained later.

4.Size of the picture

You can modify the size of a picture by two ways. The first one is to shrink or to enlarge it to fill the size you want.

Menu image\image size, a small window appears. Adjust the width and the height as you want. The case “preserve aspect ratio” keeps the same ratio between width and height, if you change the width, the height will be change, and vice versa. To change the ratio of the picture you have to untick this case. The case “optimize” gives a better result.

Enlarge a picture means an important quality loss. To enlarge, as to shrink it, using integers to multiply or divide the size gives better results.

The second way to modify a picture's size is deleting or adding stripes at the top, the bottom, the left or the right of the picture. It's usefull to easily add a line or a column in source pictures.

Menu image\Canvas size. A more complex window appears. The width and the height can be modified by the same way as previously. The squares below are used to locate by what side the picture is enlarged or shrinked. If the picture stays on the center, each side will be modified. If you want to add a 128 pixels width stripe at the right of the picture, place the picture at the left, the stripe will be added at the right and will be filled with color defined as “background”.

5.Selections

This tool is essential for all we will do.

Knowing keyboard shortcuts gives a huge time profit when using selections.

Make a selection

Most of the time, rectangular selections are used, but it's possible to have other shapes.

The first choice is the rectangular selection, click and drag on the picture to make the selection. Then is the round selection, then the rounded rectangle, rhombus, triangle. Then there's a tool to make a freely shaped selection, unfortunately this tool doesn't allow any precision so it won't be used. Then is a tool which can be usefull, the polygon tool allows to make freely shaped selections easily with precision. Next there's the invert icon : it unselect your selection and select everything else.

ctrl + A is a shortcul to know, it selects a whole picture.
All these tools are also available in the right click menu on a selection.

As seen above, it's possible to make a selection depending on the color thanks to magic wand tool.

To unselect or reselect something, use the “hide/show selection” icon at the top the screen.

Copy, Paste, Cut, Delete, etc ...

These words are well known to be basic functions of your computer. Indeed you will have to often use them. Copy copies a selection in the clipboard of the computer, paste will put this selection elsewhere in the picture or in another picture. Delete will replace your selection with your second color (colors are explained below). Cut copies the selection in the clipboard and deletes it on the picture.

When you paste a selection in a picture, you can move it in the picture by click and drag, you can also right click on it to display a menu.

Validate paste lets the selection where it is and unselects it. You can also do this by double click on the icon hide/show the selection as above. Paste options is usefull, you can display it by double click on the selection. This is the window displayed :

The opacity adjust the trensparance of the selection where you can to paste it, it will be used to make glass or mirror effects for example …

Once the transparency case ticked, the pixels of the displayed colored pixels will be transparent.

The case automatic antialiasing clears the edges of the selection when you validate the paste. This function is horrible for pixel-art.

The transformation “free …” allows to do the same as distort but with more precision. Modifying the angle makes the selection turn, modifying the scale will modify the size of your selection, modifying the offset makes the selection move horizontaly or verticaly, modifying the skew on the chosen axis will incline your selection. The “direct preview” case allows you to see directly what you do on your select

The keyboard shortcul ctrl+shift+v creates a new picture with your selection inside.

Selection antialisasing

When you do something inside a selection, borders of the selections are antialiased. To avoid this, right click on the selection, antialiasing\none :

Let's sum up the keyboard shortcuts :
  • ctrl + o : open
  • ctrl + s : save
  • ctrl + shift + s : save as
  • ctrl + n : new
  • ctrl + c : copy
  • ctrl + x : cut
  • ctrl + v : paste
  • ctrl + shift + v : paste in a new picture
  • ctrl + z : undo the last modifying
  • ctrl + y : redo the last undone modifying
  • ctrl + a : select all the picture

6.Colors

If you have a picture you have colors, these are managed at the top right of the screen as you can see :

Let's see how it works … There are two main colors, the first one is used with the left click of the mouse with all tools. The second one can be used with the right click of the mouse with some tools. The double arrow between the both colors can invert them. The colors you can see below has all basic colors you can use, clicking on the icons under them can change the color selection.

Voila pour l'interface, voyons maintenant les manipulations plus avancées … En cliquant sur une des deux couleurs sélectionnées, une fenêtre apparait vous permettant de modifier la couleur au bit près, ça peut être utile à l'occasion … On se penchera plus sur l'outil pipette déjà vu plus haut. Lorsqu'une couleur est sélectionnée avec l'outil pipette, un nombre hexadécimal s'affiche alors.

Let's see more advanced things … Clicking on one of the selected colors makes a window appear, it allows you to modify a color bit by bit, it can be usefull. When you select a color with the pipette tool, a hexadecimal number is displayed.The hew number begins with a #.

Hexadecimal means that a number is written with digits from 0 to F instead of 0 to 9 in the decimal system. This way of writing numbers is better for the computer to manage colors.

This number can be used most of the time when you manage colors on the screen. Each color is between 00 to FF in hexadecimal, in decimal system FF is 255. This number is composed of six digits, each color is composed of three basic ones : red, green and blue (RGB) mixed to have different colors. The hew number is composed of three times two digits : the red, the green and the blue.

Here there's 00 for the three colors so it's black. If there was FF for the three colors, there would be white. When each colors has the same value, it's grey, if there's more blue the color will tend blue, etc …

Remember that it's possible to use pipette tool keeping ctrl on the picture.

When two colors are mixed with 50% of each one, the color values are the middle of the two previous values.

Keep cool, it's not necessary to use the calculator to make colors, it's just good to know how does it works.

7.Gradients

To make some round effects it's sometimes necessary ot make gradients of colors. Click on the gradient icon at the top of the screen after having defines the selection which contains the graident.

So this windows appears :

The two first settings are “duotone” or “monochromatic”. Duotone (defined as default) gives a gradient vetween two defined colors. Monochromatic makes a gradient between the defined color and the trensparency (the color loses intensity in the gradient). Below are the possible directions from the color 1 to the color 2. For example, left to right gives a gradient from the color 1 at left to the color 2 at right.

Below are the colors, no use to tell you how does it work, you can also ajust the opacity of the color. Making a gradient between 100% black and 0% black is the same as making a monochromatic gradient of 100% black.

The “preview” icon gives you a preview on the picture.

8.Replace color

Remplacer une couleur peut être utile si veut facilement remplacer tous les pixels d'une même couleur dans une image ou une sélection par une autre couleur. Menu réglages\remplacer une couleur :

Replace color can be useful to replace all pixels of a color in a picture or a selection with another color. Menu Adjust\replace color

So :

The color 1 is the color you want to replace, the color 2 is the color which replaces the color 1. The tolerance is the max difference between a color and the color 1 to be replaced.

Use a 0 tolerance will replace only pixels which are exactly the color you defined.
This technic will be useful to manage special colors or some other things.

So click “Ok” and all pixels of the color 1 will be replaced by the color 2.

9.Replace color range

Just below Replace color there is Replace color range :

The color 1 and the tolerance are the same as above. However the others settings aren't the same. Pixels of the color 1 or nearby colors will change of color range to have the color range of the color 2. Here for example, blue pixels will get red. This tool allows to change easily the color of a selection witheout deleting contrasts but it doesn't always give a good result. You can also change colors with color balance in the adjust menu if you know how to use it.

10.Colored layers

This tool is very simple but don't always use it.

Menu filter\color\colored layer… so :

This tool applies a color on the selection or the picture with transparency. Here the picture's pixels would be mixed with red (70% of the previous color, 30% of red). If you use a 100% opacity, all the selection will be completely red.

The invert case gives some strange results but we can believe that it retires the selected colors … (we CAN believe).

11.Formats

Photofiltre can save pictures in the most currents formats.
* bmp : basic and heavy picture

  • png : bmp but compressed, no quality loss,transparency management (24 bits or 32 bits with transparency)
  • jpg : well known format, definitly not good fot pixel-art since it deteriorate the picture.
  • gif : well known format because it allows to make animated pictures (with the good software), only 256 colors.

The source pictures for Simutrans are in .png 24 bits. It's also possible to modify the colors quality of the picture (the colors'amount you want to use) with the idexed colors tool at the top of the screen. Photofiltre saves by default .png pictures in .png 24 bits so we won't have to modify this.

It's the end of this introduction to Photofiltre, there are many things to know but unfortunately there aren't any possible exercises to learn them but keep cool, you can return on this page to find some forgotten things, the next chapter contains many re