A digital radiography detector has a two-dimensional array of photosensors disposed in rows and columns. As a result, means for performing lateral movement of the article supporting body can be omitted, and hence the overall device can be constituted in a simple and inexpensive manner. The composition is an aqueous solution including alkali metal or ammonium cations, phosphorus containing anions and silicon containing anions as well as optionally a peroxide or a compound of Al, Ti, Zr or any mixture of them. The frame disposed between the LGP and the optical film set extends to the LGP and covers a portion of the LGP. The fan module is aligned with the channel for generating upward a flow of cooling air upward to the channel.