Event Setup Guide
This guide explains how to configure openZinkBooth for a photo booth event — including kiosk mode, always-on display, photo saving, custom frames, print calibration, and what to expect from the printer during heavy use.
- Recommended App Settings
- Enabling Photo Saving
- Always-On Display
- Screen Pinning (Kiosk Mode)
- Custom Frames
- Print Calibration
- Printer Heat & Throttling
- Pre-Event Checklist
Open Settings in openZinkBooth and configure the following before the event:
| Setting | Notes |
|---|---|
| Front / Back camera | Choose based on your booth setup — front camera faces guests, back camera typically produces higher quality |
| Flash | Enable if the venue is dimly lit. On Android 14+ the front camera uses Screen Flash automatically |
| Frame | Select your event frame in advance — see Custom Frames |
Everything else (filter, self-timer, shutter sound) can be left at its default or adjusted during the event as needed.
These are configured under Settings → Change printer → Printer Settings:
| Setting | Recommended value | Notes |
|---|---|---|
| Sleep Timer | Always On | Prevents the printer from going to sleep between guests |
| Auto-Off | Always On | Prevents the printer from turning off automatically during the event |
By default the app does not save photos to disk. To enable saving:
- Go to Settings → Storage location
- Tap the field and pick a folder using the system folder picker
- All photos taken from that point on will be saved as JPEG files in the selected folder
Tip
Create a dedicated folder such as Pictures/PhotoBooth before the event so all photos are easy to find afterwards.
To disable saving again, tap Clear storage location in Settings.
To prevent the screen from turning off between guests, enable the always-on / stay-awake setting on the device.
- Open the Settings app
- Go to Display
- Tap Screen timeout and set it to the maximum value (e.g. 30 minutes or Never)
This method keeps the screen on whenever the device is charging — ideal for a booth that runs plugged in:
- Go to Settings → About phone
- Tap Build number seven times to enable Developer Options
- Go to Settings → System → Developer Options
- Enable Stay awake (Screen will never sleep while charging)
Note
Make sure the device is plugged in during the event so the screen stays on reliably.
- Settings → Display → Screen timeout → set to maximum
- Alternatively use the Developer Options method above
Screen pinning locks the device to openZinkBooth so guests cannot leave the app or access other parts of the phone.
- Go to Settings → Security (or Biometrics and security) → App pinning
- On some devices: Settings → Advanced features → Screen pinning
- Turn App pinning on
- Optionally enable Ask for PIN before unpinning to prevent guests from disabling it
- Open openZinkBooth so it is in the foreground
- Open the Recents screen (the square or gesture button)
- Tap the app icon at the top of the openZinkBooth card
- Tap Pin (or Pin this app)
The app is now pinned. Guests cannot navigate away from it.
- Press and hold Back + Recents simultaneously, then confirm the PIN if prompted
- On gesture-navigation devices: swipe up and hold to open Recents, then tap the app icon → Unpin
Tip
Test the pin/unpin flow yourself before the event starts so you can quickly reclaim the device if needed.
openZinkBooth supports custom overlay frames that are composited on top of the photo before printing.
| Property | Requirement |
|---|---|
| Format | PNG with alpha channel (transparency) |
| Color mode | RGBA (32-bit) |
| Orientation | Portrait |
Match the frame resolution exactly to your printer model for the sharpest result:
| Printer | Resolution |
|---|---|
| HP Sprocket 200 / 200D / Studio | 640 × 1002 px |
| HP Sprocket 400 | 793 × 972 px |
| HP Sprocket Select | 768 × 1152 px |
- Leave the center area transparent — that is where the photo will show through
- Place your design (borders, logos, text, decorations) around the edges using fully opaque or semi-transparent pixels
- Avoid placing important design elements too close to the very edge — the printer may clip 1–2 mm on each side
- Export at 96 DPI or higher
- Save the PNG to the device (e.g. via USB, cloud storage, or AirDrop)
- In openZinkBooth go to Settings → Frames
- Tap + and select your PNG file
- Give it a name and confirm
- The frame now appears in the frame picker on the Preview screen
The HP Sprocket stretches prints slightly and may shift the image vertically depending on the unit. If you notice that prints are cropped or have an uneven border, you can compensate for this in the app.
- Connect to your printer
- Go to Settings → Change printer → Printer Settings
- Scroll to the Calibration section
- Enable Output Correction
To calibrate precisely, print the test image below. It shows the full 640×1002 px print area with a millimetre ruler on all four sides, a centre cross, and labelled edges.
Download full size (640×1002 px)
How to read the result:
- Red border equally wide on all four sides — calibration is correct
- Red border narrower at the top than at the bottom → image is shifted upward → adjust Top Offset
- Red border too narrow on both top and bottom (but equal left/right) → image is stretched vertically → adjust Vertical Scale
- Centre cross — should appear exactly in the centre of the printed output
| Setting | What it does |
|---|---|
| Vertical Scale | Compresses the image slightly in height to compensate for the printer stretching it. Default: 0.9524 (≈ 1/1.05) |
| Top Offset | Adds white padding at the top to shift the image down. Default: 46 px (≈ 3.5 mm) |
The red border in the test image is exactly 8 mm wide on all four sides. The vertical ruler runs from 0 to 76 mm, with tick marks every 5 mm.
Print the test image without Output Correction first (or with Vertical Scale = 1.0 and Top Offset = 0) to see the raw printer output.
Step 1 — Calculate Top Offset (vertical shift):
Measure the red border at the top of your print with a ruler (top_mm). The target is 8 mm.
Top Offset = (8.0 mm - top_mm) × 13.18 px
Example: measured top border = 5.5 mm → Top Offset = (8.0 mm − 5.5 mm) × 13.18 px = 33 px
Example: measured top border = 9.8 mm → Top Offset = (8.0 mm − 9.8 mm) × 13.18 px = −24 px
Step 2 — Calculate Vertical Scale (stretch correction):
Measure from the 0 mm mark to each of the following marks on the side ruler: 10, 20, 30, 40, 50, 60 and 70 mm. For each measurement divide the expected value by your measured value. Then average all seven results — that is your Vertical Scale.
| Measure from 0 to… | Expected | Your measurement | Calculation |
|---|---|---|---|
| 10 mm mark | 10 mm | e.g. 10.4 mm | 10 ÷ 10.4 = 0.962 |
| 20 mm mark | 20 mm | e.g. 20.9 mm | 20 ÷ 20.9 = 0.957 |
| 30 mm mark | 30 mm | e.g. 31.3 mm | 30 ÷ 31.3 = 0.958 |
| 40 mm mark | 40 mm | e.g. 41.8 mm | 40 ÷ 41.8 = 0.957 |
| 50 mm mark | 50 mm | e.g. 52.2 mm | 50 ÷ 52.2 = 0.958 |
| 60 mm mark | 60 mm | e.g. 62.6 mm | 60 ÷ 62.6 = 0.958 |
| 70 mm mark | 70 mm | e.g. 73.1 mm | 70 ÷ 73.1 = 0.958 |
Add all seven results and divide by 7 → Vertical Scale = 0.958
Workflow:
- Print the test image with Output Correction disabled (or Vertical Scale =
1.0, Top Offset =0) - Measure the red border at the top and the ruler tick spacing with a ruler
- Calculate Top Offset and Vertical Scale using the formulas above and enter them
- Enable Output Correction and print again — the red border should now be equally wide (~8 mm) on all four sides
- Repeat if necessary — usually one iteration is enough
Note
Calibration values vary between individual printer units. The defaults were measured on an HP Sprocket 200 and are a good starting point for most devices.
Tip
Once you have found the right values for your printer, write them down — if you reinstall the app you will need to enter them again.
The HP Sprocket uses ZINK (Zero Ink) thermal printing technology. The print head generates significant heat during each print job.
- Normal operation: A single print takes approximately 45–60 seconds
- After several consecutive prints: The printer may slow down noticeably as internal temperature rises
- Overheating protection: When the printer gets too hot it will pause automatically and wait until it has cooled down before continuing. This is normal behaviour and not a fault
- The app will show
Overheatingin the printer status when this occurs
- Do not cover the printer — keep the ventilation area (bottom and sides) unobstructed
- Place the printer on a hard, flat surface, not on fabric or inside a box
- If you are running a high-volume booth, keep a second charged Sprocket as a backup and alternate between the two
- Let the printer rest for 2–3 minutes after every 10 consecutive prints if possible
- Avoid placing the printer in direct sunlight or near other heat sources
Warning
Do not attempt to cool the printer with a fan or by placing it in front of air conditioning. Rapid temperature changes can affect print quality and may damage the device.
Note
The automatic cool-down pause does not lose the print job. The app will resume and complete the job once the printer reports it is ready again.
Run through this list before guests arrive:
- Printer is charged (or on charge) and has enough paper loaded
- App connected to printer — status shows Connected
- Printer Sleep Timer set to Always On
- Printer Auto-Off set to Always On
- Correct frame selected
- Test print done — check for cropping or misalignment, adjust calibration if needed
- Storage location set (if saving photos is desired)
- Screen timeout set to maximum or Stay awake enabled
- Device is plugged into power
- Screen pinning enabled and tested
- App pinned — verify you cannot swipe away
- Know the unpin gesture/PIN in case you need to reclaim the device