My fork of Scott Kellum's (@scottkellum) and Team-Sass' Modular Scale that adds the option for a separate scale for negative multiples.

I really like the idea of a modular scale but it is always difficult to pick a ratio that works well for larger sizes (positive multiples) and smaller sizes (negative multiples). If the positive multiples progress at a pleasing rate—the negative multiples get too small too quickly to be of much use. And if a ratio works for negative multiples, it seems the sizes of positive multiples increased too slowly.

This is similar to the issues discussed by Scott Bradley (@vangogh) of Vanseo Design in his How To Use Size, Scale, And Proportion In Web Design post (see his Typographic Scale illustration).

To correct this, I have modified the Modular Scale code so that a different ratio for negative multiples can now be defined ($ratio-negative). If set to false (the default), the standard ratio ($ratio) is used for both positive and negative values.

Let's look at the following table comparing the values for the perfect fourth scale (1.333) for all multiples versus the perfect fourth scale for positive multiples and the major second scale (1.125) for negative multiples.

The positive multiples for the 1.333 ratio progress nicely—but the negative multiples get too small much too quick. The first step goes from 16 to 12—a very big jump. The second step is 9. And at only the third step the value is a very small 7.

Now compare this to the column where the ratio for negative multiples is 1.125. You still get the nice 1.333 ratio progression for positive multiples, and the negative multiples get smaller at a much more usable rate. The following chart illustrates this.

###Multibases and Multiratios Removed I have also removed the multibase and multiratio features because they made things much more complicated programmatically and their use, from a design standpoint, doesn't make much sense to me. Two scales laid on top of each other usually creates a stair-step effect and, IMO, goes against the idea of a smooth scale. The chart below illustrates this stair-step effect as the values for the multibase scale jump between the values of each base's scale.

I understand that there may be a need for multiple scales on a page—but I think they should be interacted with independent of each other.

###Removed Gem Files To avoid issues with the Modular Scale gem, I have "de-Gemified" the code so it is now a self-contained .scss file with no dependencies.

Copyright (c) 2011 Scott Kellum (@scottkellum), Adam Stacoviak (@adamstac) and Mason Wendell (@codingdesigner)

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