Image layers not saved

Hello,

I'm currently plotting 3 layers in 1 figure as a result of my PIV measurements

• Grayscale image
• Magnitude matrix (a matrix for Alpha is applied for transparency)
• Vector arrows (using patch function)

After plotting I zoom to a part I want to save. I go: file --> save as --> TIFF image (or eps/or pdf/etc). When opening the saved file, only the last layer (the vector arrows) are shown on a white background. If I save the file without zooming everything goes well. I can't figure out why this is happening. Any help is greatly appreciated!