Is there a way to increase the thickness of all lines in a group?

[Lynnette7]

I have some coloring book pages that I'm working on. I have lots of groups that each contain multiple thicknesses of lines. I need to make the ones closer to the front a touch darker than those in the distance. Is there a way to select a group and add .25 thickness to every line in the group? (Or whatever other increment needed.)

[Mylenium]

Select a line, then use the select similar function from the menu and change the strokes. You may need to enter isolation mode by double-clicking on groups to not select too much.

Mylenium 

[Kevin Stohlmeyer]

You can select based on depth using the Layers panel.

The top most layers are the closest.

Shift-click the gap between the circle and the end of the panel (blue square) to select.

Once you have your depth selected you can adjust the stroke or Group them as needed.

[pixxxelschubser]

@Lynnette7 

1. You have different groups of paths with different line thicknesses in a layer - right?
2. All paths (of a group) should become thicker by the same value, in addition to the existing line thickness?
3. All strokes have the same colour?

Try this (sorry for my German UI):

select your group

Add menu: Effekt -> Path -> Outline Stroke

Nothing happens - only the small circle to the right of the group name is filled now

Create a new layer and drag the whole group onto this new layer

and click on the circle with a red border (in the screenshot) to the right of the name of the layer.

Add a new stroke in the Appearance Panel

Set the stroke width as desired, but double the width as the new stroke will automatically be aligned in the middle. (I have coloured the contour yellow so that it is easier to see.)

Done!

[Ton Frederiks]

I have a script by @rcraighead that resizes selected paths by percentage, but I cannot find it anymore on this forum: scalePathWidth.jsx

I don't want to post it without his permission.

[Lynnette7]

This would be lovely to have and is exactly what I'm looking for. I can't figure out why this isn't a built-in feature in Illustrator. It seems like it would be needed quite often. Thank you. I'll wait to see if he responds. 

[pixxxelschubser]

@Lynnette7 

Doesn't the solution I suggested work? Or have I completely misunderstood your requirement?

[Lynnette7]

Hi, thanks for your detailed explanation, however, I'm looking for something easy. 🙂 I would love to be able to select a group, click an up (or down) arrow, and have them scale up or down in proportion to each other at a selected scale. (.25, or whatever else is set.) I can currently open a group and select all of the same strokes, as @Mylenium suggested and increase them one type (thickness) at a time, but I was looking for something easier. I'm always looking for shortcuts and your way seems pretty complicated - as in, lots of steps. It's the steps I'm seeing if I can get around. 🙂 

[pixxxelschubser]

Give it a try. It may look complicated - but it's not. With just a few clicks, you can add the extra stroke width to all elements of a group at the same time.

The biggest advantage for the future: Once created, you can adjust the additional stroke width at any time by simply changing the stroke property in the Appearance panel.

Disadvantage: The additional contour is added all around.

[Monika Gause]

Increasing the stroke width by a certain percentage is not the same as making them all 0.25 pt bolder.

[Lynnette7]

Yes, I understand that. Thanks.

[Kevin Stohlmeyer]

The issue if I understand it correctly is the paths are already various sizes and @Lynnette7 you want them consistent based on depth in the image?

If that is the case, the scalepathwidth wouldnt work - it would scale the various strokes not make them consistent.

[Lynnette7]

Say I have a flower that has 300 strokes/paths of varying widths. If want to make the WHOLE flower bolder (all the various path widths in proportion to each other), I'm not finding an easy, super simple, one-click method to do that.

[Lynnette7]

Oh, I found this, which I think is what @Ton Frederiks was talking about. The thread is here: https://community.adobe.com/t5/illustrator-discussions/how-to-apply-a-brush-and-keep-stroke-weights/...

And the specific message I'm referring to contains this...
_______

This should work. Make sure to enter the percentage with a decimal point.

//by Ray Craighead
//Resize selected path stroke width(s) by percentage.

function scalePathWidth(){
    var aDoc = app.activeDocument;
    var sel = app.selection;
    if (sel.length < 1){
        alert ('Make a selection of paths and try again');
        return;
        }
    else
    {
        var myInput;
        userPrompt();
        var myPercent;
        function userPrompt(){
            myInput = prompt('Scale Percentage (0.1 = 100%)', .100);
            myPercent = Number(myInput);
            }
        for (var i = 0; i < sel.length; i++) {
                var myWidth = sel[i].strokeWidth;
                sel[i].strokeWidth = myWidth * myPercent;
                }
            }
        }

scalePathWidth();

And here's a .jsx file you can download and install:
https://www.dropbox.com/s/yjg7jrj7wkak5p8/scalePathWidth.jsx?dl=0 Edit: I noticed I left an unused variable so I updated the script.
_______

The Dropbox link no longer works. So I wondered if anyone smarter at coding than me knows what unused variable needs to be fixed in the script?

[Ton Frederiks]

That is indeed the script I was referring to and it works as it is (probably also corrected on the forum page). So copy the script, create a Text Only file, paste the script and save it with a .js or .jsx extension. Install it or load it with File > Script > Other Script...

[Lynnette7]

Thank you. Sorry to be slow to reply. I've had a very long day at work. Will try this tomorrow or Friday when I have time to get back to Illustrator. 

[Kurt Gold · Accepted solution]

There are two simple, about twenty years old scripts by Muchacho (stroke_plus and stroke_minus) that increase or decrease all selected strokes by 0.5 pt.

They still work in current versions of Illustrator. Increase/Decrease values can be modified in line 5 and 6.

Download Stroke Plus/Minus

[Lynnette7]

Thanks!

[Lynnette7]

This script works in groups, which is exactly what I wanted. The other script does not work if all the lines are in a group. Thanks for posting. And thanks to the original creator of the scripts, too! 

[pixxxelschubser]

Both scripts shown by @Kurt Gold  do what I think @Lynnette7 wants.

The scripts also work in groups and with compound paths.

Further:
All scripts shown here in the thread so far work exclusively with point as a unit. (But this could easily be changed).

Two questions remain:

1. What unit of measurement does Lynnette7 use for the stroke width?
2. Does Lynnette7 want to change the thickness once in the scripts shown by Kurt or does she prefer the input option via @rcraighead's dialogue box?

[Lynnette7]

First I'm going to try the percentages option. I just need some time when I'm not wiped from work to try these out. Thanks for all your help!

[Lynnette7]

Okay, I know I'm being slow on this. Just got a major project off and now have a little more time to deal with this. So I tried the script that I posted earlier (From Ray Craighead) and I can't get it to work. 
I pasted the code into Notepad, saved it with a .jsx extension, put it into the scripts folder in Illustrator. When I have my Illustrator file that I want to work on open, I select the group that I want to make bolder (thicken the lines) and go to File/Scripts. The script is there, but when I click it and the dialogue box pops up and I enter a decimal and hit okay or return, it does nothing. The line thicknesses do not change and no step is added to the history panel. 

Thoughts for me on what I'm doing wrong?

[Monika Gause]

Probably it doesn't like groups - did you try and ungroup the lines?

[Ton Frederiks]

What do you enter? When I enter 1.5 or 2 it works. But only Undo is added to the History panel.

[Ton Frederiks]

Yes, Monika is right, it does not like groups...