In Excel, you can use Subtotal or Aggregate functions to summarize data across multiple criteria. Here are the steps to do so:

1. Select the range of cells or table that contains the items to sum.
2. On the Data tab, in the Outline group, click Subtotal.
3. In the Subtotal dialog box, select the summary function (SUM, for example).
4. Select the column to sum (Values), and then add subtotals for each unique value in the specified column.
5. Select the group-by columns (Color, for example).
6. Click OK.