Put very simply, value refers to how light or dark a particular colour is. Value is also relative to the other colours around it. For example, a yellow next to a deep purple might have a light value, but if the same yellow was placed next to white it would have a medium value. Value is a very useful thing to understand in quilting, and can be used to create some pretty amazing effects.
TECHNIQUES FOR LOOKING AT VALUE:
Within a single colour group, it's reasonably easy to sort value by eye. For example, this set of greens:
The very light and very dark value greens are quite obvious, not quite so much for the three middle ones. There are a couple of quick and easy ways to figure this out.
Ruby Glass/ Value Finder
One readily available, cheap tool is a ruby glass, or value finder. It's essentially a see-through piece of red plastic (I would imagine red cellophane would also work.) When you look through the ruby glass, the colour of the fabric is washed out, and you're left with the relative value of each piece.
It was tricky to photograph, but this is the same set of greens photographed through the ruby glass. As you can see the mid-value greens are difficult to separate even with the colour washed out. The third and fourth could possibly even be switched around.
One negative aspect of the ruby glass is that it is not especially useful when looking at the value of red-based colours (red, pink, orange) as they all look extremely light.
Black and White Photos:
The other easy way to do it is by taking a photo and then using a photo editing program to change the image to black and white. I love Picmonkey for this - it's free, easy to use and quick.
Simply upload your photo, go to the second tab down on the left (Effects) and click on Black and White.
When you're working with fabrics with several colours in them (especially larger prints) and a wide range of different colours, working out their relative values can be a little trickier.
For example these Anna Maria Horner prints (the same ones I used in my Retro Flowers quilt, which is what inspired this post). I quickly laid these out, in roughly what I thought was value order.
This is the same set of fabrics, with the picture taken through the ruby glass. As you can see, the bottom four on the left have pretty much washed out as they're all red based colours. So not such a useful technique for looking at the relative value of this set of fabric.
But, if we make the photo black and white, it becomes easier to see the relative value. Because some of these have a large contrast in value within the one print, it is pretty subjective as to where it might be placed relative to the other fabrics. I also think it's a matter of experience - the more you practice looking a the value of different sets of fabric, the better you'll get - and honestly I'm a newbie quilter so I don't have a whole lot of experience ;o)
Based on the above photo, I rearranged them into what I thought might be value order.
As you can see from the black and white version, I could probably keep playing with the order to get a better array from dark through to light. The reason I've left the deep blues at the left hand side is that to me, the blue dominates more than the lighter colours in each of the fabrics (but that's probably quite subjective). Another thing to consider is that these are only small areas of the fabrics - if you wanted to get a really good idea of the value of large scale prints, it would work more effectively if you photographed a larger area.
I think this is a really good thing to practice, and something I will be doing when I'm designing quilts from now on :o)
LOOKING AT VALUE ACROSS A WHOLE QUILT:
The techniques above can obviously be used when looking at value distribution across a whole quilt. When I was playing around with the layout for my Retro Flowers quilt and asked for some feedback, there were a couple of other suggestions for techniques you can use.
In my cry for help post, I had narrowed down my quilt layout to three options. Kathy clicked the 'Pin It' button, which then pops up all the photos from a web page so you can choose which one to add to Pinterest. She said this was a great way to compare the three layouts side by side and work out which one was the most balanced.
Changing the Image Size
A really great suggestion came from Susan (The Bored Zombie) about reducing the image size of your photo. Susan has been told that if you're image isn't interesting at 200x200 pixels, it probably isn't interesting larger either.
Picmonkey to the rescue again! Simply go to the 'Crop' button, and in the box where it says Actual Size, enter 200 in both the boxes. Click the button next to 'Scale Photo', and make sure you've dragged the crop box around your whole image. Then click the apply button.
This will reduce your photo to 200x200, which does make it easier to assess the value distribution. This is the 200x200 version of my Retro Flowers quilt top - and looking at this I probably could have distributed the value a bit better!
I hope this post has been helpful - I'm only just starting to learn about value and how to use it to good effect in quilts, so this is really just the tip of the iceberg as far as value theory goes. If you're interested in further reading, some very talented quilty ladies put together the Value Added QAL last year, and covered a lot of different aspects of how to use value in quilts for particular effects. The bloggers involved also designed four different quilts that rely strongly on value for their design.
Understanding Value with Leila at Where the Orchids Grow
Leading the Eye with Value with Amy Badskirt
Value Patterns in Quilts with Rachel at Stitched in Colour
Value Dynamics with Jolene at Blue Elephant Stitches