Tag Archives: color scheme

Advanced Tips For Selecting A Grout Color

The primary reason for grouting tiled surfaces is to prevent water from penetrating behind the tile and weakening the adhesive or the backer and the structure beneath the backer. In mosaic artwork, the grout also has a visual function, and that is to contrast (not match) the tile colors. If the grout color does not sufficiently contrast the tile colors, than all the tiles blend together visually, and much of the “mosaic effect” is lost.

Grout Color Should Contrast Not Match

There are some novices who doubt my advice about contrasting grout color and even try to match their grout color to the tile colors. These are the people who later email me in a complete panic. They usually use the words “completely ruined” to describe what grouting did to their once beautiful mosaic, and from the pictures they send, I’m inclined to agree with them. (Note that these mosaics can be saved, but it requires either scraping the grout out with a grout removal tool or painting the grout with acrylic paint or some other ad hoc solution.)

A Medium Gray Grout

Since experience has shown time and again that the best grout color is one that contrasts tile color, the question becomes which grout color best contrasts ALL the different colors used in the mosaic. For MOST combinations of tile colors, the best contrast is usually provided by a medium to dark gray, with darker being the better guess if in doubt. Always keep in mind that the color of the grout will be significantly lighter when fully cured compared to how it looks when wet.

A Notable Exception: Lighter Blues

There are a few notable exceptions to the rule of gray grout being best. The most obvious exception is when you are using gray tile (duh), but the one that usually catches people by surprise is when tiles of lighter blue colors are used. Unfortunately, these are just the shades of blue that are popular for water and sky elements, so this is a significant exception. In this situation, a warm light brown or sand colored grout might be a good choice for contrasting the blue tile, but what if there are light brown tile used elsewhere in the mosaic? Is there a good standby color of grout for this situation? The answer is no, but there is a quick solution.

Go Look At Grout Colors With Your Tile

Building material stores such as Home Depot and Lowes usually carry about 30 or more colors of grout, and they have color swatches on the shelves and/or packaging so that you can pick out grout similar to how you pick out paint, only with much more limited options. The trick or tip is to not to try to do this from memory without the benefit of having your tile with you. Take one or two tile of each color used in the mosaic with you to the store and hold them up against the color swatches. I have even gone into the store with small mosaics, just as I have taken in parts of plumbing I was trying to match or replace. Don’t be self conscious about it. The people who work there are accustomed to seeing professionals at work, and you will be quite unobtrusive compared to the building contractors dealing with emergencies. At least you won’t be covered in dirt and holding a toilet seat or something like that.

Some “Advanced” Tips

From the many emails and pictures I have received in the past 12+ years, I can state with some confidence that novices tend to regret choosing grout colors as an attempt to add another color to the mosaic. Matching grout color to tile color tends to be even more disastrous.

If you already have your figures rendered in tile using a relatively small grout gap, and you like how those figures look, then your main objective while grouting should be to not mess up the visual art that was already working, especially if you are a novice at mosaic.

Of course, even a novice can take a few of each color tile and create an abstract experiment on a scrap piece of plywood and try a novel grout color on it.

The monochromatic nature of medium gray grout makes it contrast colors intrinsically, in the same way that back and white contrast colors intrinsically. All three are balanced in hue. The keep-it-simple and less-is-more principles really come into play when you decide to second guess some shade of medium to dark gray when grouting figurative mosaic artwork.

On the other hand, there are all those earth tones to play with…

Just remember to experiment on a piece of scrap before trying it out on a mosaic where 90% of the work was spent cutting and mounting the tile.

How To Estimate Mosaic Colors Using Photoshop Elements

Irregular Shapes

It’s easy to estimate the total area of a rectangular or circular mosaic using our tile estimator, but it can be much more difficult if the shape of the mosaic is irregular. In fact, most of the individual color fields in a mosaic are arranged in irregular shapes, unless you are doing an abstract geometrical pattern.

How do you estimate the area covered by an individual color when it is arranged in irregular shapes throughout a mosaic design?

The following is a method using Photoshop Elements.

Use Digital Images

If you get the image into the computer, the computer already knows how many pixels are that color and the total number of pixels in the image.

The trick is to find some way for the computer to tell us this information, and there are probably many image editing software packages that could be used in some way to do it. I used Photoshop Elements because that was what I had installed. I would think GIMP and other freeware imaging packages could be adapted in some way as well.

This method uses Photoshop’s Magic Extractor to cut out the color field, then turning that color field black and putting it on a white background. In the RBG color mode used by JPEGs, white has a value of 255 and black has a value of 0. If we take an average of the value of all pixels, this weighted average divided by 255 will represent the percent of the image area that is NOT the particular color.

Photoshop Elements Example

For this example, we will use a jpeg of Henri Matisse’s painting “The Dance” and find the percent of the total area that is covered by blue.

matisse-the-dance-v1

Henri Matisse painting “The Dance”

Tip: When you make your own mosaic designs, don’t use one blue color for an area such as this. Instead, use two or even three blues of the same hue but slightly different in shade and mix them together to create visual interest. Note how Matisse’s bold color fields aren’t completely homogenized, even in this digital copy of low resolution.

Step 1. Use The Magic Extractor To Clip Out The Color Of Interest

Use the Magic Extractor in Photoshop Elements to clip out the color.

matisse-color-extractor

Image > Magic Extractor has a + highlighter for marking the color you want to save and a second highlighter for marking all the colors you want to delete. You can use the Preview button to see if you have things marked correctly.

Note that I used the first highlighter to mark the blue in multiple places to make sure that I marked all the different shades of blue. I also marked it in each separate blue area just to be sure, but this isn’t necessary. When I used the second highlighter, I made sure I marked the grass and the dancers in a way that got all the different colors and shades of colors used for them.

matisse-post-extraction

Magic Extractor results in Photoshop Elements

Notice how efficiently the Magic Extractor removes the non-blue elements.

Step 2. Use Filter Tools To Black Out The Color

matisse-adjust-threshold

Filter > Adjustments > Threshold

Under the Filter menu, there is a collection of tools called Adjustments. Use the Threshold tool, and drag the pointer to 255. What this is doing is saying black out all color with RBG values under 255, which is the RBG for pure white.

Step 3. Save As A JPEG With A White Background.

Notice that the gridded background is not colored at all, which means the image is now a Photoshop file PSD instead of a JPEG. We need to save it as a JPEG with a white background before we can proceed. However, first you should save this PSD file in case you need to backtrack for whatever reason, and then save it as a JPEG.

Once you have saved it as a JPEG, close this PSD file and open the newly created JPEG.

matisse-jpeg-white

Open the JPEG with a white background

 Step 4. Use Filter Tools To Set Every Pixel To The Average Color.

Now comes the real trick of how to find out how many pixels were in the blue area that we turned to black. Photoshop has a tool that will turn every pixel to the average of all the pixel’s current RBG values. All of our pixels are white (RBG = 255) or black (RBG = 0). The weighted average of all these pixels will be a gray with an RBG somewhere between 0 and 255. The larger the blacked area was before the averaging, the darker the gray will be and the lower the RBG number. The Average tool is found under the Filter menu: Filter > Average or Filter > Blur > Average.

matisse-filter-average

Filter > Blur > Average

Step 5. Use The Color Picker Tool To Find The RBG Value Of The Gray.

 

matisse-color-picker

matisse-color-picker

Photoshop’s Color Picker tool is the eyedropper icon. Use it to click the image and then the “Select Foreground Color” square at the bottom of the left toolbar.

Use Photoshop’s Color Picker tool (eyedropper icon) to click the image and then click the “Select Foreground Color” square. This square is at the bottom of the left toolbar. Once you click the square, the dialog window will pop open and show you the RBG (red blue green) values for this gray. Since it is a gray averaged from pure white and pure black, all the RBG values should be the same number.

In our example, we see that the RBG value for the gray is 149. If we divide 149 by 255, we get 0.58, which means that 58% of the image’s area is the whited-out non-blue colors. To get the percent of the total area that is blue, we subtract 58% from 100% and get 42%.

Why this works: If the mosaic was completely whited out, then the RBG number we found using the Color Picker would be 255, the number of white. But some of the mosaic was our blacked-out blue area. Black has an RBG number of 0. When all the white pixels (255) were averaged with the black pixels (0), the number calculated for this average was 149. Dividing 149 by 255 tells us the ratio of white area to total area. Grays with a higher RBG number mean that the amount of white area before averaging was larger.

So let’s say you were making a 6 ft x 4 ft mosaic interpretation of this Matisse painting. The total area is 6 ft x 4 ft = 24 square feet. The area that is blue is 0.42 x 24 square feet =  10.1 square feet.

You can find out how many tiles you need to cover that blue area using our tile estimator, which has a table of different tile sizes per square foot based on a standard grout gap.

Faster and Easier Than It Seems

Note that you will need to do this for all your colors (you can find the area of the last colors by subtracting the rest from 100%). However, this isn’t very much work. In fact, once you do it a few times, you can do this sort of analysis easily and quickly. Keep in mind that if a color isn’t used anywhere but in small areas like trimming and borders, then it might be difficult to block it out using the Magic Extractor tool, but do you really need a close estimate of something that is only used in 5% of the area? (If so, you need to use a higher resolution pattern, and do the analysis in sections.) Also, you can save that color for last and find it’s area by subtracting all the other color area estimates from 100%.