ramé-hart Technical Document

Technical Bulletin

Frequently Asked Tech Support Questions

Nov 2025

Below are the most commonly asked technical support questions and the answers.

Q1. When I attempt to measure contact angle, I get an "Error in Profile" message.

A1. There are several possible reasons for this error. However, the most common cause is the location of the baseline. In the screenshot below, you will see two red tick marks on the left and right sides of the static image window midway between the top and bottom of the window. If you are attempting to measure contact angle on a sessile drop (drop sitting on a surface), then the baseline must be below the red tick marks. When the baseline is below the red tick marks, DROPimage is looking for a sessile drop. When the baseline is above the red tick marks, DROPimage is looking for a pendant drop (e.g., to measure its surface tension). See also the first tip in this video.

There are other conditions that can also cause the "Error in profile" condition. It usually has to do the placement of the baseline and lighting. If you are unable to resolve the error, then follow the instructions on this video to send us a screenshot along with your instrument serial number. Click on contact us for the email address. And we will respond with specific guidance.

Q2. I have an Automated Dispensing System and DROPimage Advanced, but when I click on Device Control on the pull-down menu, the "Drop volume control" option is grayed out.

A2. Click on Edit > Options and under "Installed options", check on "Drop volume control". If prompted to install the dispenser, say "Yes". In most cases, this will resolve the issue. Note that if you start up DROPimage with the dispenser turned off, you will get one error and then DROPimage will turn off "Drop volume control" to avoid future error messages. Thus, the fix is to simply return to Options and turn it back on. In some rare cases, the dispenser will not initialize because it's on the wrong COM port. In that case, watch this video which details how to change the COM port settings. Note that by default, COM1 is assigned to the Automated Dispensing System, COM2 is assigned to the Automated Tilting Base, COM3 to the Oscillator, and COM4 to any Temperature Controller.

Q3. I have DROPimage Pro and the icon for the dispenser disappeared.

A3. See answer A2 above.

Q4. When I go the use the Automated Tilting Base, the option is grayed out.

A4. See answer A2 above but under "Installed options", check on "Tilting base control".

Q5. When I start DROPimage, I get a message that says "Interface not supported".

A5. This error indicates that there is no communication between the camera and DROPimage. See this tech bulletin for a detailed troubleshooting guide.

Q6. I'm trying to measure the contact angle of a new liquid on a new solid but I don't know the densities and surface tension values for these materials.

A6. Don't worry about it. Contact angle is a 100% geometric calculation. The only time density and surface tension components are required is when measuring surface energy.

Q7. I measured the surface tension of a unknown liquid. I realized later that I entered the wrong density. How can I calculate the corrected surface tension now that I have the correct density value without redoing the measurement?

A7. No problem. Since the surface tension is directly proportional to the density, you can simply calculate a correction factor by dividing the correct density value by original incorrect value and then use this correction factor to adjust the density value. For example, let's suppose you used a density of 0.9 g/cm³ to measure the surface tension of a liquid and the surface tension measured 40 mN/m. Then later you learn that the correct density is really 1.2 g/cm³. In this case, divide 1.2 by 0.9 to get a correction factor of 1.334. Now to apply the correction factor, simply multiply the original surface tension value of 40 mN/m by 1.334 and the new corrected surface tension is 53.334 nN/m.

Q8. Our instrument has DROPimage Advanced. When I start the program, two windows appear. However, today when I started it, only one large window appeared. How do I fix it?

A8. DROPimage Advanced can be operated in two different modes: Single-window and two-window mode. Click on View > Start pass-thru to start the small live video window. To learn how to toggle between one-window and two-window modes, watch this video.

If you require any additional technical assistance, please contact us with your serial number and the nature of your inquiry.