1. The baking time is too long or the baking temperature is too high 2. Insufficient exposure time 3. The photosensitive paste is applied too thick or unevenly 4. The concentration of the developing solution is too high 5. The development time is too long 6. The photosensitive paste has deteriorated 7. Other harmful light entering

We were established by foreign trade staff after studying from overseas in 2008, the team was composed by a number ? We were established by foreign trade staff after studying from overseas in 2008, the team was composed by a number 7?