# PDF optimisation report

## Method

Only the **image streams** inside each PDF were recompressed. Page content streams, text, embedded fonts, ToUnicode CMaps, shading patterns and gradients, link annotations and document structure were left untouched.

- Images downsampled to a **150 dpi** ceiling based on the size they are actually drawn at on the page
- Re-encoded as **JPEG quality 88**; soft masks (transparency) recompressed to match
- Images under 20 KB, bitonal images and CMYK separations left alone
- Files re-saved linearised ("fast web view") with object streams

Ghostscript was tried first and rejected: it produced smaller files but corrupted the ToUnicode CMaps, so copied or searched text came out as mojibake.

## Verification

Every file was checked for: extracted text byte-identical to the original after whitespace normalisation; identical page count; identical link-annotation count; and a page-by-page rendered-pixel comparison at 110 dpi against the original.

## Results

| File | Before | After | Saved | Worst-page PSNR |
|---|---:|---:|---:|---:|
| `BCA_Capital_Services_Overview.pdf` | 4.40 MB | 0.63 MB | 86% | 37.4 dB |
| `BCA_Corporate_Profile.pdf` | 13.31 MB | 9.11 MB | 32% | 43.9 dB |
| `BCA_Domain_01_Capital_Readiness.pdf` | 1.16 MB | 0.48 MB | 59% | 39.3 dB |
| `BCA_Domain_02_Transaction_Structuring.pdf` | 8.95 MB | 0.49 MB | 94% | 39.0 dB |
| `BCA_Domain_03_DaDD_Diagnostics.pdf` | 0.84 MB | 0.44 MB | 48% | 42.2 dB |
| `BCA_Domain_04_Capital_Advisory.pdf` | 8.65 MB | 0.45 MB | 95% | 42.5 dB |
| `BCA_Domain_05_Capital_Raising.pdf` | 8.80 MB | 0.57 MB | 93% | 42.9 dB |
| `BCA_Domain_06_Corporate_Finance.pdf` | 0.39 MB | 0.23 MB | 40% | 44.1 dB |
| `BCA_Domain_07_Fractional_CFO_Services.pdf` | 0.94 MB | 0.46 MB | 51% | 46.3 dB |
| `BCA_Domain_08_Business_Strategy.pdf` | 8.87 MB | 0.48 MB | 95% | 39.0 dB |
| `BCA_Domain_09_Evaluation_and_Audit.pdf` | 0.90 MB | 0.50 MB | 45% | 39.3 dB |
| `BCA_Domain_10_Real_Estate_Advisory.pdf` | 5.75 MB | 0.50 MB | 91% | 37.4 dB |
| `BCA_Domain_11_Corporate_Access_and_Introductions.pdf` | 0.88 MB | 0.59 MB | 33% | 41.4 dB |
| **Total** | **63.8 MB** | **14.9 MB** | **77%** | |

PSNR above ~35 dB is the threshold below which JPEG artefacts become perceptible on photographic content; all files clear it. All visible differences are confined to photographs — vector text, rules and gradients are pixel-identical.

## Note on the Corporate Profile

`BCA_Corporate_Profile.pdf` only came down 32% (13.3 → 9.1 MB) because most of its weight is genuine vector artwork — 4.6 MB across 229 form XObjects — not images. Reducing it further means changing the design, not the compression.