Tracking change over time
One scan tells you where you are. The question you actually have is whether it is working, and that needs two.
Choose what you are comparing against
You can set your latest scan against either:
- Your first scan — the whole distance travelled
- Your last scan — what changed this week
Both are useful and they answer different questions. Week to week is noisy; against your first scan is where a real trend shows.
Your first scan cannot show change. It is the baseline everything else is measured against, so on your first one there is nothing to compare and Densy says so rather than drawing a flat line.
When a stand-in photo is used
Sometimes the scan you would compare against has an unclear capture for that particular area. Rather than compare against something unreadable, Densy steps back to the nearest usable one and labels it — Last clear photo, or Earliest clear photo.
That label is the honest version. Calling a stand-in “your previous scan” would be the misleading one.
Why the photos sit side by side
Two captures are shown next to each other rather than under a drag-across slider.
A slider needs both photographs lined up pixel for pixel, and scalp photos taken by hand a week apart are not. Sliding two photos that are slightly differently framed makes the change look bigger than it is — so the comparison would flatter you, which is worse than useless.
You can also switch a photograph between As taken and Enhanced, where the contrast is raised so the finest hairs show up.
What an unclear capture does to your numbers
There are three outcomes, not two, and the difference matters:
| How the photo came out | What you get |
|---|---|
| Clear | Numbers, and a comparison |
| Usable but not confident | Numbers, but no statement about what changed |
| Too unclear to read | The photograph, and no numbers at all |
The middle one is the one people misread. Densy is not hiding the reading — it has one, and it is declining to tell you a difference it cannot stand behind.
You may see an older explanation on one screen saying an unclear area’s numbers are held near your last clear scan. That is not what happens — nothing is substituted. An unclear area either shows numbers without a comparison, or shows no numbers.
Usually it is low light or a moved camera, and your next scan picks the area back up. See Taking your weekly scan for how to avoid it.
Signs of new growth
Where Densy sees a possible sign of new growth, it says how many areas and calls it something to watch over the next few scans, not a confirmed result.
Take that literally. It is an early signal, and the whole point of a weekly record is that you get to find out whether it holds.
Your hair-loss stage
Your stage is read from your latest scan photographs and placed on one of two scales, depending on the sex you gave at intake:
| Scale | Range |
|---|---|
| Norwood | Stage I to VII |
| Sinclair | Grade 1 to 5 |
There is one reading per scan, and a trend showing whether it has moved.
A stage is an estimate from close-up photographs, not a doctor’s examination. Trust the mirror too. It becomes more reliable as you add scans.
Two things can leave it blank, and both tell you which:
- No stage yet — there is no scan to read one from.
- Tell us your sex — the two scales are not interchangeable, so without that answer there is no scale to place you on.
What next
- Understanding your results — what the bands and figures mean
- Your scan history — every scan you have taken
- Hair Coach — ask about one specific scan