Don't deduct volunteer time, but ...
Your time is valuable, but that doesn't matter to the IRS when it comes to volunteering at a charity.
You can't claim the value of your wages for the hours spent helping out at your favorite nonprofit. Neither can you count as a deduction the value of a project you created, such as a poster that you, a graphic artist, designed for the charity.
But you can deduct other costs associated with your charity work. This includes your mileage in connection with the group's work, which can be claimed on Schedule A at the rate of 14 cents per mile.
You also can claim as a charitable deduction unreimbursed out-of-pocket expenses.
As with all things tax, keep good records. Track your charitable travel and hang on to the receipts for the poster board and special markers you bought just for the nonprofit's poster project.