I made a post about dying lines and had some inquiries as to how I do that. I will photograph some lines tomorrow and add them to the thread when I have them. What they will show are factory color and dyed color for comparison.
I have done this quite a few times over the years and never had a problem. I do it just like this:
1. Remove line from spool
2. Wipe line with cloth wet with warm soapy water, squeeze as you pull line through
3. Wrap line into lose coils about six inch inside diameter and set aside
4. Heat about one quart of water to boiling point and turn off burner
Place large oven proof glass bowl in sink and fill with hot tap water to temper bowl
5. After bowl has sat a minute or so dump out the tap water
6. Place about 1 - 1.5 tea spoon of your choice Rit Dye in bottom of bowl and add a few ounces of the water from the stove 'Carefully' I like a tea pot for this.
7. Stir the dye and allow it to begin dissolving
8. Now add the rest of the water so it's at least 3" deep in your bowl or etc.
9. Stir to mix solution
10. Set timer to 45 seconds
11. Place line in lose coils into bowl and use spoon to push it into dye evenly
12. Now start timer
13. While timer runs keep busy pushing the line under the surface of the dye solution and sort of stir a little (Not a lot of stirring, but lots of pushing it under)
14. When timer goes off, see if the line is beginning to color (it should be. Keep going until color looks solid, (usually another 15 - 20 seconds.
15. Add an ounce of white vinegar (eyeball it) no need to measure, stir solution keep pushing any floating line under
16. Turn on warm tap water and slide bowl under flow, purge water from bowl with steady flow of warm water (Do not use cold water)
17. As all the dye solution is purged from bowl add a shot of dish detergent and stir line around (you can use your hands now.
18. Step 17 washes and rinses the line of any dye that has not set.
19. Making sure you don't get a tangled mess carefully unravel the coils, if you did this right (lots of pushing it under the dye but not too much stirring) the line will unravel easily enough
20. Now pull the dyed line through paper towels; keep good tension on as you pull line through the towels. You may have to take a new spot if your towel gets wet where you have pulled 20 foot or so through.
That's it, you will be amazed at how little color ends up on those paper towels, especially if you washed the line well with dish soap after purging the dye from the bowl. Remember do not purge with 'COLD' water, use good warm / hot tap water to flush the dye out of the bowl. Non of mine have ever went wrong, the color is solid like the one in the picture below (running line on a Spey line dyed coco brown) and they float just fine. I dress lines with mucilin and don't notice any color coming off on my dressing pads either
For color examples; a light mint green line will go almost as well as white to whatever color you want as long as it's darker than the mint green. I have done three of these gray and they are as good as factory color. Yellow will go brown, olive green, or bright green. You can have light blue, royal blue, etc. just buy the color dye you want but be mindful of the base color of the line when you are choosing the color for the dye.
This is a good move if you get a killer deal on a good line but hate the color. Florescent orange I've never done but it would go to brown better than anything else I can think of.
One last word here, if you are apprehensive about the color you can do a test with as little as an inch of the rear part of a weight forward line. This would be dying the end of the running line and you don't have to worry about it not looking right if you do a test on the extreme end of any line.
Here's that 89 dollar Spey line with the running line dyed coco, I did the tip also and it is better now for swinging wets to salmon and etc.