Humidity and temperature fluctuations in your cleanroom are two very influential factors affecting the dimensional stability of your film, therefore directly affecting the performance of your film.
Use this tool to determine film size change effects due to humidity and temperature changes in in order to determine the appropriate course of action:
1.    You may need to select a PCB film that has lower humidity coefficient for size change (see KODAK ACCUMAX Photoplotter Film ARD7). A low humidity coefficient film will immediately deliver a reduction in size change variability without the need for investment in new AC or humidity controls.
2.    You may want to consider upgrades to the environmental controls in your cleanroom.
After launching the application, you will be asked to enter the following:
Critical Film Length of Interest (e.g. diagonal): A value up to 9999 millimeters
Change in relative humidity: range: -10 to +10%
Change in temperature: range -10 to +10 degrees Centigrade
Humidity coefficient of film being measured: range: 0.0009% - 0.0015% change per % change in RH
Temperature coefficient of polyester: A constant for all polyester films: 0.0018% per degree Centigrade.
The Calculator will show you the size change in microns
* JavaScript must be enabled to use the Size Change Calculator Application.